#if defined(_WIN32)
#define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005
#else
#define _XOPEN_SOURCE 600 // For flockfile() on Linux
#define _LARGEFILE_SOURCE // Enable 64-bit file offsets
#define __STDC_FORMAT_MACROS // <inttypes.h> wants this for C++
#endif

#if defined(__SYMBIAN32__)
#define NO_SSL // SSL is not supported
#define NO_CGI // CGI is not supported
#define PATH_MAX FILENAME_MAX
#endif // __SYMBIAN32__

#ifndef _WIN32_WCE // Some ANSI #includes are not available on Windows CE
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#endif // !_WIN32_WCE

#include <time.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>

#if defined(_WIN32) && !defined(__SYMBIAN32__) // Windows specific
#define _WIN32_WINNT 0x0400 // To make it link in VS2005
#include <windows.h>

#ifndef PATH_MAX
#define PATH_MAX MAX_PATH
#endif

#ifndef _WIN32_WCE
#include <process.h>
#include <direct.h>
#include <io.h>
#else // _WIN32_WCE
#include <winsock2.h>
#define NO_CGI // WinCE has no pipes

typedef long off_t;
#define BUFSIZ  4096

#define errno   GetLastError()
#define strerror(x)  _ultoa(x, (char *) _alloca(sizeof(x) *3 ), 10)
#endif // _WIN32_WCE

#define MAKEUQUAD(lo, hi) ((uint64_t)(((uint32_t)(lo)) | \
            ((uint64_t)((uint32_t)(hi))) << 32))
#define RATE_DIFF 10000000 // 100 nsecs
#define EPOCH_DIFF MAKEUQUAD(0xd53e8000, 0x019db1de)
#define SYS2UNIX_TIME(lo, hi) \
    (time_t) ((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF)

// Visual Studio 6 does not know __func__ or __FUNCTION__
// The rest of MS compilers use __FUNCTION__, not C99 __func__
// Also use _strtoui64 on modern M$ compilers
#if defined(_MSC_VER) && _MSC_VER < 1300
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ "line " STR(__LINE__)
#define strtoull(x, y, z) strtoul(x, y, z)
#define strtoll(x, y, z) strtol(x, y, z)
#else
#define __func__  __FUNCTION__
#define strtoull(x, y, z) _strtoui64(x, y, z)
#define strtoll(x, y, z) _strtoi64(x, y, z)
#endif // _MSC_VER

#define ERRNO   GetLastError()
#define NO_SOCKLEN_T
#define SSL_LIB   "ssleay32.dll"
#define CRYPTO_LIB  "libeay32.dll"
#define DIRSEP '\\'
#define IS_DIRSEP_CHAR(c) ((c) == '/' || (c) == '\\')
#define O_NONBLOCK  0
#if !defined(EWOULDBLOCK)
#define EWOULDBLOCK  WSAEWOULDBLOCK
#endif // !EWOULDBLOCK
#define _POSIX_
#define INT64_FMT  "I64d"

#define WINCDECL __cdecl
#define SHUT_WR 1
#define snprintf _snprintf
#define vsnprintf _vsnprintf
#define sleep(x) Sleep((x) * 1000)

#define pipe(x) _pipe(x, BUFSIZ, _O_BINARY)
#define popen(x, y) _popen(x, y)
#define pclose(x) _pclose(x)
#define close(x) _close(x)
#define dlsym(x,y) GetProcAddress((HINSTANCE) (x), (y))
#define RTLD_LAZY  0
#define fseeko(x, y, z) fseek((x), (y), (z))
#define fdopen(x, y) _fdopen((x), (y))
#define write(x, y, z) _write((x), (y), (unsigned) z)
#define read(x, y, z) _read((x), (y), (unsigned) z)
#define flockfile(x) (void) 0
#define funlockfile(x) (void) 0

#if !defined(fileno)
#define fileno(x) _fileno(x)
#endif // !fileno MINGW #defines fileno

typedef HANDLE pthread_mutex_t;
typedef struct {HANDLE signal, broadcast;} pthread_cond_t;
typedef DWORD pthread_t;
#define pid_t HANDLE // MINGW typedefs pid_t to int. Using #define here.

struct timespec {
    long tv_nsec;
    long tv_sec;
};

static int pthread_mutex_lock(pthread_mutex_t *);
static int pthread_mutex_unlock(pthread_mutex_t *);
static FILE *mg_fopen(const char *path, const char *mode);

#if defined(HAVE_STDINT)
#include <stdint.h>
#else
typedef unsigned int  uint32_t;
typedef unsigned short  uint16_t;
typedef unsigned __int64 uint64_t;
typedef __int64   int64_t;
#define INT64_MAX  9223372036854775807
#endif // HAVE_STDINT

// POSIX dirent interface
struct dirent {
    char d_name[PATH_MAX];
};

typedef struct DIR {
    HANDLE   handle;
    WIN32_FIND_DATAW info;
    struct dirent  result;
} DIR;

#else    // UNIX  specific
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <stdint.h>
#include <inttypes.h>
#include <netdb.h>

#include <pwd.h>
#include <unistd.h>
#include <dirent.h>
#if !defined(NO_SSL_DL) && !defined(NO_SSL)
#include <dlfcn.h>
#endif
#include <pthread.h>
#if defined(__MACH__)
#define SSL_LIB   "libssl.dylib"
#define CRYPTO_LIB  "libcrypto.dylib"
#else
#if !defined(SSL_LIB)
#define SSL_LIB   "libssl.so"
#endif
#if !defined(CRYPTO_LIB)
#define CRYPTO_LIB  "libcrypto.so"
#endif
#endif
#define DIRSEP   '/'
#define IS_DIRSEP_CHAR(c) ((c) == '/')
#ifndef O_BINARY
#define O_BINARY  0
#endif // O_BINARY
#define closesocket(a) close(a)
#define mg_fopen(x, y) fopen(x, y)
#define mg_mkdir(x, y) mkdir(x, y)
#define mg_remove(x) remove(x)
#define mg_rename(x, y) rename(x, y)
#define ERRNO errno
#define INVALID_SOCKET (-1)
#define INT64_FMT PRId64
typedef int SOCKET;
#define WINCDECL

#endif // End of Windows and UNIX specific includes

#include "mongoose.h"

#define MONGOOSE_VERSION "3.0"
#define PASSWORDS_FILE_NAME ".htpasswd"
#define CGI_ENVIRONMENT_SIZE 4096
#define MAX_CGI_ENVIR_VARS 64
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))

#if defined(DEBUG)
#define debug(...) do { \
    flockfile(stdout); \
    printf("###%lu.%p.%s: ", \
            (unsigned long) time(NULL) - start_time, (void *) pthread_self(), \
            __func__); \
    printf(__VA_ARGS__); \
    putchar('\n'); \
    fflush(stdout); \
    funlockfile(stdout); \
} while (0)
#else
#define debug(...)
#endif // DEBUG

#if defined(DEBUG_TRACE)
#define DEBUG_TRACE(x) do { \
    flockfile(stdout); \
    printf("###%lu.%p.%s: ", \
            (unsigned long) time(NULL) - start_time, (void *) pthread_self(), \
            __func__); \
    printf x; \
    putchar('\n'); \
    fflush(stdout); \
    funlockfile(stdout); \
} while (0)
#else
#define DEBUG_TRACE(x)
#endif // DEBUG

// Darwin prior to 7.0 and Win32 do not have socklen_t
#ifdef NO_SOCKLEN_T
typedef int socklen_t;
#endif // NO_SOCKLEN_T

typedef void * (*mg_thread_func_t)(void *);

static const char *http_500_error = "Internal Server Error";

// Snatched from OpenSSL includes. I put the prototypes here to be independent
// from the OpenSSL source installation. Having this, mongoose + SSL can be
// built on any system with binary SSL libraries installed.
typedef struct ssl_st SSL;
typedef struct ssl_method_st SSL_METHOD;
typedef struct ssl_ctx_st SSL_CTX;

#define SSL_ERROR_WANT_READ 2
#define SSL_ERROR_WANT_WRITE 3
#define SSL_FILETYPE_PEM 1
#define CRYPTO_LOCK  1

#if defined(NO_SSL_DL)
extern void SSL_free(SSL *);
extern int SSL_accept(SSL *);
extern int SSL_connect(SSL *);
extern int SSL_read(SSL *, void *, int);
extern int SSL_write(SSL *, const void *, int);
extern int SSL_get_error(const SSL *, int);
extern int SSL_set_fd(SSL *, int);
extern SSL *SSL_new(SSL_CTX *);
extern SSL_CTX *SSL_CTX_new(SSL_METHOD *);
extern SSL_METHOD *SSLv23_server_method(void);
extern int SSL_library_init(void);
extern void SSL_load_error_strings(void);
extern int SSL_CTX_use_PrivateKey_file(SSL_CTX *, const char *, int);
extern int SSL_CTX_use_certificate_file(SSL_CTX *, const char *, int);
extern int SSL_CTX_use_certificate_chain_file(SSL_CTX *, const char *);
extern void SSL_CTX_set_default_passwd_cb(SSL_CTX *, mg_callback_t);
extern void SSL_CTX_free(SSL_CTX *);
extern unsigned long ERR_get_error(void);
extern char *ERR_error_string(unsigned long, char *);
extern int CRYPTO_num_locks(void);
extern void CRYPTO_set_locking_callback(void (*)(int, int, const char *, int));
extern void CRYPTO_set_id_callback(unsigned long (*)(void));
#else
// Dynamically loaded SSL functionality
struct ssl_func {
    const char *name;   // SSL function name
    void  (*ptr)(void); // Function pointer
};

#define SSL_free (* (void (*)(SSL *)) ssl_sw[0].ptr)
#define SSL_accept (* (int (*)(SSL *)) ssl_sw[1].ptr)
#define SSL_connect (* (int (*)(SSL *)) ssl_sw[2].ptr)
#define SSL_read (* (int (*)(SSL *, void *, int)) ssl_sw[3].ptr)
#define SSL_write (* (int (*)(SSL *, const void *,int)) ssl_sw[4].ptr)
#define SSL_get_error (* (int (*)(SSL *, int)) ssl_sw[5].ptr)
#define SSL_set_fd (* (int (*)(SSL *, SOCKET)) ssl_sw[6].ptr)
#define SSL_new (* (SSL * (*)(SSL_CTX *)) ssl_sw[7].ptr)
#define SSL_CTX_new (* (SSL_CTX * (*)(SSL_METHOD *)) ssl_sw[8].ptr)
#define SSLv23_server_method (* (SSL_METHOD * (*)(void)) ssl_sw[9].ptr)
#define SSL_library_init (* (int (*)(void)) ssl_sw[10].ptr)
#define SSL_CTX_use_PrivateKey_file (* (int (*)(SSL_CTX *, \
                const char *, int)) ssl_sw[11].ptr)
#define SSL_CTX_use_certificate_file (* (int (*)(SSL_CTX *, \
                const char *, int)) ssl_sw[12].ptr)
#define SSL_CTX_set_default_passwd_cb \
    (* (void (*)(SSL_CTX *, mg_callback_t)) ssl_sw[13].ptr)
#define SSL_CTX_free (* (void (*)(SSL_CTX *)) ssl_sw[14].ptr)
#define SSL_load_error_strings (* (void (*)(void)) ssl_sw[15].ptr)
#define SSL_CTX_use_certificate_chain_file \
    (* (int (*)(SSL_CTX *, const char *)) ssl_sw[16].ptr)

#define CRYPTO_num_locks (* (int (*)(void)) crypto_sw[0].ptr)
#define CRYPTO_set_locking_callback \
    (* (void (*)(void (*)(int, int, const char *, int))) crypto_sw[1].ptr)
#define CRYPTO_set_id_callback \
    (* (void (*)(unsigned long (*)(void))) crypto_sw[2].ptr)
#define ERR_get_error (* (unsigned long (*)(void)) crypto_sw[3].ptr)
#define ERR_error_string (* (char * (*)(unsigned long,char *)) crypto_sw[4].ptr)

// set_ssl_option() function updates this array.
// It loads SSL library dynamically and changes NULLs to the actual addresses
// of respective functions. The macros above (like SSL_connect()) are really
// just calling these functions indirectly via the pointer.
static struct ssl_func ssl_sw[] = {
    {"SSL_free",   NULL},
    {"SSL_accept",   NULL},
    {"SSL_connect",   NULL},
    {"SSL_read",   NULL},
    {"SSL_write",   NULL},
    {"SSL_get_error",  NULL},
    {"SSL_set_fd",   NULL},
    {"SSL_new",   NULL},
    {"SSL_CTX_new",   NULL},
    {"SSLv23_server_method", NULL},
    {"SSL_library_init",  NULL},
    {"SSL_CTX_use_PrivateKey_file", NULL},
    {"SSL_CTX_use_certificate_file",NULL},
    {"SSL_CTX_set_default_passwd_cb",NULL},
    {"SSL_CTX_free",  NULL},
    {"SSL_load_error_strings", NULL},
    {"SSL_CTX_use_certificate_chain_file", NULL},
    {NULL,    NULL}
};

// Similar array as ssl_sw. These functions could be located in different lib.
static struct ssl_func crypto_sw[] = {
    {"CRYPTO_num_locks",  NULL},
    {"CRYPTO_set_locking_callback", NULL},
    {"CRYPTO_set_id_callback", NULL},
    {"ERR_get_error",  NULL},
    {"ERR_error_string", NULL},
    {NULL,    NULL}
};
#endif // NO_SSL_DL

static const char *month_names[] = {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

// Unified socket address. For IPv6 support, add IPv6 address structure
// in the union u.
struct usa {
    socklen_t len;
    union {
        struct sockaddr sa;
        struct sockaddr_in sin;
    } u;
};

// Describes a string (chunk of memory).
struct vec {
    const char *ptr;
    size_t len;
};

// Structure used by mg_stat() function. Uses 64 bit file length.
struct mgstat {
    int is_directory;  // Directory marker
    int64_t size;      // File size
    time_t mtime;      // Modification time
};

// Describes listening socket, or socket which was accept()-ed by the master
// thread and queued for future handling by the worker thread.
struct socket {
    struct socket *next;  // Linkage
    SOCKET sock;          // Listening socket
    struct usa lsa;       // Local socket address
    struct usa rsa;       // Remote socket address
    int is_ssl;           // Is socket SSL-ed
    int is_proxy;
};

enum {
    CGI_EXTENSIONS, CGI_ENVIRONMENT, PUT_DELETE_PASSWORDS_FILE, CGI_INTERPRETER,
    PROTECT_URI, AUTHENTICATION_DOMAIN, SSI_EXTENSIONS, ACCESS_LOG_FILE,
    SSL_CHAIN_FILE, ENABLE_DIRECTORY_LISTING, ERROR_LOG_FILE,
    GLOBAL_PASSWORDS_FILE, INDEX_FILES,
    ENABLE_KEEP_ALIVE, ACCESS_CONTROL_LIST, MAX_REQUEST_SIZE,
    EXTRA_MIME_TYPES, LISTENING_PORTS,
    DOCUMENT_ROOT, SSL_CERTIFICATE, NUM_THREADS, RUN_AS_USER,
    NUM_OPTIONS
};

static const char *config_options[] = {
    "C", "cgi_extensions", ".cgi,.pl,.php",
    "E", "cgi_environment", NULL,
    "G", "put_delete_passwords_file", NULL,
    "I", "cgi_interpreter", NULL,
    "P", "protect_uri", NULL,
    "R", "authentication_domain", "mydomain.com",
    "S", "ssi_extensions", ".shtml,.shtm",
    "a", "access_log_file", NULL,
    "c", "ssl_chain_file", NULL,
    "d", "enable_directory_listing", "yes",
    "e", "error_log_file", NULL,
    "g", "global_passwords_file", NULL,
    "i", "index_files", "index.html,index.htm,index.cgi",
    "k", "enable_keep_alive", "no",
    "l", "access_control_list", NULL,
    "M", "max_request_size", "16384",
    "m", "extra_mime_types", NULL,
    "p", "listening_ports", "8080",
    "r", "document_root",  ".",
    "s", "ssl_certificate", NULL,
    "t", "num_threads", "10",
    "u", "run_as_user", NULL,
    NULL
};
#define ENTRIES_PER_CONFIG_OPTION 3

struct mg_context {
    volatile int stop_flag;       // Should we stop event loop
    SSL_CTX *ssl_ctx;             // SSL context
    char *config[NUM_OPTIONS];    // Mongoose configuration parameters
    mg_callback_t user_callback;  // User-defined callback function
    void *user_data;              // User-defined data

    struct socket *listening_sockets;

    volatile int num_threads;  // Number of threads
    pthread_mutex_t mutex;     // Protects (max|num)_threads
    pthread_cond_t  cond;      // Condvar for tracking workers terminations

    struct socket queue[20];   // Accepted sockets
    volatile int sq_head;      // Head of the socket queue
    volatile int sq_tail;      // Tail of the socket queue
    pthread_cond_t sq_full;    // Singaled when socket is produced
    pthread_cond_t sq_empty;   // Signaled when socket is consumed
};

struct mg_connection {
    struct mg_connection *peer; // Remote target in proxy mode
    struct mg_request_info request_info;
    struct mg_context *ctx;
    SSL *ssl;                   // SSL descriptor
    struct socket client;       // Connected client
    time_t birth_time;          // Time connection was accepted
    int64_t num_bytes_sent;     // Total bytes sent to client
    int64_t content_len;        // Content-Length header value
    int64_t consumed_content;   // How many bytes of content is already read
    char *buf;                  // Buffer for received data
    int buf_size;               // Buffer size
    int request_len;            // Size of the request + headers in a buffer
    int data_len;               // Total size of data in a buffer
};

const char **mg_get_valid_option_names(void) {
    return config_options;
}

static void *call_user(struct mg_connection *conn, enum mg_event event) {
    conn->request_info.user_data = conn->ctx->user_data;
    return conn->ctx->user_callback == NULL ? NULL :
        conn->ctx->user_callback(event, conn, &conn->request_info);
}

static int get_option_index(const char *name) {
    int i;

    for (i = 0; config_options[i] != NULL; i += ENTRIES_PER_CONFIG_OPTION) {
        if (strcmp(config_options[i], name) == 0 ||
                strcmp(config_options[i + 1], name) == 0) {
            return i / ENTRIES_PER_CONFIG_OPTION;
        }
    }
    return -1;
}

const char *mg_get_option(const struct mg_context *ctx, const char *name) {
    int i;
    if ((i = get_option_index(name)) == -1) {
        return NULL;
    } else if (ctx->config[i] == NULL) {
        return "";
    } else {
        return ctx->config[i];
    }
}

// Print error message to the opened error log stream.
static void cry(struct mg_connection *conn, const char *fmt, ...) {
    char buf[BUFSIZ];
    va_list ap;
    FILE *fp;
    time_t timestamp;

    va_start(ap, fmt);
    (void) vsnprintf(buf, sizeof(buf), fmt, ap);
    va_end(ap);

    // Do not lock when getting the callback value, here and below.
    // I suppose this is fine, since function cannot disappear in the
    // same way string option can.
    conn->request_info.log_message = buf;
    if (call_user(conn, MG_EVENT_LOG) == NULL) {
        fp = conn->ctx->config[ERROR_LOG_FILE] == NULL ? NULL :
            mg_fopen(conn->ctx->config[ERROR_LOG_FILE], "a+");

        if (fp != NULL) {
            flockfile(fp);
            timestamp = time(NULL);

            (void) fprintf(fp,
                    "[%010lu] [error] [client %s] ",
                    (unsigned long) timestamp,
                    inet_ntoa(conn->client.rsa.u.sin.sin_addr));

            if (conn->request_info.request_method != NULL) {
                (void) fprintf(fp, "%s %s: ",
                        conn->request_info.request_method,
                        conn->request_info.uri);
            }

            (void) fprintf(fp, "%s", buf);
            fputc('\n', fp);
            funlockfile(fp);
            if (fp != stderr) {
                fclose(fp);
            }
        }
    }
    conn->request_info.log_message = NULL;
}

// Return OpenSSL error message
static const char *ssl_error(void) {
    unsigned long err;
    err = ERR_get_error();
    return err == 0 ? "" : ERR_error_string(err, NULL);
}

// Return fake connection structure. Used for logging, if connection
// is not applicable at the moment of logging.
static struct mg_connection *fc(struct mg_context *ctx) {
    static struct mg_connection fake_connection;
    fake_connection.ctx = ctx;
    return &fake_connection;
}

const char *mg_version(void) {
    return MONGOOSE_VERSION;
}

static void mg_strlcpy(register char *dst, register const char *src, size_t n) {
    for (; *src != '\0' && n > 1; n--) {
        *dst++ = *src++;
    }
    *dst = '\0';
}

static int lowercase(const char *s) {
    return tolower(* (const unsigned char *) s);
}

static int mg_strncasecmp(const char *s1, const char *s2, size_t len) {
    int diff = 0;

    if (len > 0)
        do {
            diff = lowercase(s1++) - lowercase(s2++);
        } while (diff == 0 && s1[-1] != '\0' && --len > 0);

    return diff;
}

static int mg_strcasecmp(const char *s1, const char *s2) {
    int diff;

    do {
        diff = lowercase(s1++) - lowercase(s2++);
    } while (diff == 0 && s1[-1] != '\0');

    return diff;
}

static char * mg_strndup(const char *ptr, size_t len) {
    char *p;

    if ((p = (char *) malloc(len + 1)) != NULL) {
        mg_strlcpy(p, ptr, len + 1);
    }

    return p;
}

static char * mg_strdup(const char *str) {
    return mg_strndup(str, strlen(str));
}

// Like snprintf(), but never returns negative value, or the value
// that is larger than a supplied buffer.
// Thanks to Adam Zeldis to pointing snprintf()-caused vulnerability
// in his audit report.
static int mg_vsnprintf(struct mg_connection *conn, char *buf, size_t buflen,
        const char *fmt, va_list ap) {
    int n;

    if (buflen == 0)
        return 0;

    n = vsnprintf(buf, buflen, fmt, ap);

    if (n < 0) {
        cry(conn, "vsnprintf error");
        n = 0;
    } else if (n >= (int) buflen) {
        cry(conn, "truncating vsnprintf buffer: [%.*s]",
                n > 200 ? 200 : n, buf);
        n = (int) buflen - 1;
    }
    buf[n] = '\0';

    return n;
}

static int mg_snprintf(struct mg_connection *conn, char *buf, size_t buflen,
        const char *fmt, ...) {
    va_list ap;
    int n;

    va_start(ap, fmt);
    n = mg_vsnprintf(conn, buf, buflen, fmt, ap);
    va_end(ap);

    return n;
}

// Skip the characters until one of the delimiters characters found.
// 0-terminate resulting word. Skip the delimiter and following whitespaces if any.
// Advance pointer to buffer to the next word. Return found 0-terminated word.
// Delimiters can be quoted with quotechar.
static char *skip_quoted(char **buf, const char *delimiters, const char *whitespace, char quotechar) {
    char *p, *begin_word, *end_word, *end_whitespace;

    begin_word = *buf;
    end_word = begin_word + strcspn(begin_word, delimiters);

    /* Check for quotechar */
    if (end_word > begin_word) {
        p = end_word - 1;
        while (*p == quotechar) {
            /* If there is anything beyond end_word, copy it */
            if (*end_word == '\0') {
                *p = '\0';
                break;
            } else {
                size_t end_off = strcspn(end_word + 1, delimiters);
                memmove (p, end_word, end_off + 1);
                p += end_off; /* p must correspond to end_word - 1 */
                end_word += end_off + 1;
            }
        }
        for (p++; p < end_word; p++) {
            *p = '\0';
        }
    }

    if (*end_word == '\0') {
        *buf = end_word;
    } else {
        end_whitespace = end_word + 1 + strspn(end_word + 1, whitespace);

        for (p = end_word; p < end_whitespace; p++) {
            *p = '\0';
        }

        *buf = end_whitespace;
    }

    return begin_word;
}

// Simplified version of skip_quoted without quote char
// and whitespace == delimiters
static char *skip(char **buf, const char *delimiters) {
    return skip_quoted(buf, delimiters, delimiters, 0);
}


// Return HTTP header value, or NULL if not found.
static const char *get_header(const struct mg_request_info *ri,
        const char *name) {
    int i;

    for (i = 0; i < ri->num_headers; i++)
        if (!mg_strcasecmp(name, ri->http_headers[i].name))
            return ri->http_headers[i].value;

    return NULL;
}

const char *mg_get_header(const struct mg_connection *conn, const char *name) {
    return get_header(&conn->request_info, name);
}

// A helper function for traversing comma separated list of values.
// It returns a list pointer shifted to the next value, of NULL if the end
// of the list found.
// Value is stored in val vector. If value has form "x=y", then eq_val
// vector is initialized to point to the "y" part, and val vector length
// is adjusted to point only to "x".
static const char *next_option(const char *list, struct vec *val,
        struct vec *eq_val) {
    if (list == NULL || *list == '\0') {
        /* End of the list */
        list = NULL;
    } else {
        val->ptr = list;
        if ((list = strchr(val->ptr, ',')) != NULL) {
            /* Comma found. Store length and shift the list ptr */
            val->len = list - val->ptr;
            list++;
        } else {
            /* This value is the last one */
            list = val->ptr + strlen(val->ptr);
            val->len = list - val->ptr;
        }

        if (eq_val != NULL) {
            /*
             * Value has form "x=y", adjust pointers and lengths
             * so that val points to "x", and eq_val points to "y".
             */
            eq_val->len = 0;
            eq_val->ptr = (const char *) memchr(val->ptr, '=', val->len);
            if (eq_val->ptr != NULL) {
                eq_val->ptr++;  /* Skip over '=' character */
                eq_val->len = val->ptr + val->len - eq_val->ptr;
                val->len = (eq_val->ptr - val->ptr) - 1;
            }
        }
    }

    return list;
}

#if !defined(NO_CGI)
static int match_extension(const char *path, const char *ext_list) {
    struct vec ext_vec;
    size_t path_len;

    path_len = strlen(path);

    while ((ext_list = next_option(ext_list, &ext_vec, NULL)) != NULL)
        if (ext_vec.len < path_len &&
                mg_strncasecmp(path + path_len - ext_vec.len,
                    ext_vec.ptr, ext_vec.len) == 0)
            return 1;

    return 0;
}
#endif // !NO_CGI

// HTTP 1.1 assumes keep alive if "Connection:" header is not set
// This function must tolerate situations when connection info is not
// set up, for example if request parsing failed.
static int should_keep_alive(const struct mg_connection *conn) {
    const char *http_version = conn->request_info.http_version;
    const char *header = mg_get_header(conn, "Connection");
    return (header == NULL && http_version && !strcmp(http_version, "1.1")) ||
        (header != NULL && !mg_strcasecmp(header, "keep-alive"));
}

static const char *suggest_connection_header(const struct mg_connection *conn) {
    return should_keep_alive(conn) ? "keep-alive" : "close";
}

static void send_http_error(struct mg_connection *conn, int status,
        const char *reason, const char *fmt, ...) {
    char buf[BUFSIZ];
    va_list ap;
    int len;

    conn->request_info.status_code = status;

    if (call_user(conn, MG_HTTP_ERROR) == NULL) {
        buf[0] = '\0';
        len = 0;

        /* Errors 1xx, 204 and 304 MUST NOT send a body */
        if (status > 199 && status != 204 && status != 304) {
            len = mg_snprintf(conn, buf, sizeof(buf), "Error %d: %s", status, reason);
            cry(conn, "%s", buf);
            buf[len++] = '\n';

            va_start(ap, fmt);
            len += mg_vsnprintf(conn, buf + len, sizeof(buf) - len, fmt, ap);
            va_end(ap);
        }
        DEBUG_TRACE(("[%s]", buf));

        mg_printf(conn, "HTTP/1.1 %d %s\r\n"
                "Content-Type: text/plain\r\n"
                "Content-Length: %d\r\n"
                "Connection: %s\r\n\r\n", status, reason, len,
                suggest_connection_header(conn));
        conn->num_bytes_sent += mg_printf(conn, "%s", buf);
    }
}

#if defined(_WIN32) && !defined(__SYMBIAN32__)
static int pthread_mutex_init(pthread_mutex_t *mutex, void *unused) {
    unused = NULL;
    *mutex = CreateMutex(NULL, FALSE, NULL);
    return *mutex == NULL ? -1 : 0;
}

static int pthread_mutex_destroy(pthread_mutex_t *mutex) {
    return CloseHandle(*mutex) == 0 ? -1 : 0;
}

static int pthread_mutex_lock(pthread_mutex_t *mutex) {
    return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1;
}

static int pthread_mutex_unlock(pthread_mutex_t *mutex) {
    return ReleaseMutex(*mutex) == 0 ? -1 : 0;
}

static int pthread_cond_init(pthread_cond_t *cv, const void *unused) {
    unused = NULL;
    cv->signal = CreateEvent(NULL, FALSE, FALSE, NULL);
    cv->broadcast = CreateEvent(NULL, TRUE, FALSE, NULL);
    return cv->signal != NULL && cv->broadcast != NULL ? 0 : -1;
}

static int pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex) {
    HANDLE handles[] = {cv->signal, cv->broadcast};
    ReleaseMutex(*mutex);
    WaitForMultipleObjects(2, handles, FALSE, INFINITE);
    return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1;
}

static int pthread_cond_signal(pthread_cond_t *cv) {
    return SetEvent(cv->signal) == 0 ? -1 : 0;
}

static int pthread_cond_broadcast(pthread_cond_t *cv) {
    // Implementation with PulseEvent() has race condition, see
    // http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
    return PulseEvent(cv->broadcast) == 0 ? -1 : 0;
}

static int pthread_cond_destroy(pthread_cond_t *cv) {
    return CloseHandle(cv->signal) && CloseHandle(cv->broadcast) ? 0 : -1;
}

static pthread_t pthread_self(void) {
    return GetCurrentThreadId();
}

// For Windows, change all slashes to backslashes in path names.
static void change_slashes_to_backslashes(char *path) {
    int i;

    for (i = 0; path[i] != '\0'; i++) {
        if (path[i] == '/')
            path[i] = '\\';
        // i > 0 check is to preserve UNC paths, like \\server\file.txt
        if (path[i] == '\\' && i > 0)
            while (path[i + 1] == '\\' || path[i + 1] == '/')
                (void) memmove(path + i + 1,
                        path + i + 2, strlen(path + i + 1));
    }
}

// Encode 'path' which is assumed UTF-8 string, into UNICODE string.
// wbuf and wbuf_len is a target buffer and its length.
static void to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len) {
    char buf[PATH_MAX], *p;

    mg_strlcpy(buf, path, sizeof(buf));
    change_slashes_to_backslashes(buf);

    // Point p to the end of the file name
    p = buf + strlen(buf) - 1;

    // Trim trailing backslash character
    while (p > buf && *p == '\\' && p[-1] != ':') {
        *p-- = '\0';
    }

    // Protect from CGI code disclosure.
    // This is very nasty hole. Windows happily opens files with
    // some garbage in the end of file name. So fopen("a.cgi    ", "r")
    // actually opens "a.cgi", and does not return an error!
    if (*p == 0x20 ||               // No space at the end
            (*p == 0x2e && p > buf) ||  // No '.' but allow '.' as full path
            *p == 0x2b ||               // No '+'
            (*p & ~0x7f)) {             // And generally no non-ascii chars
        (void) fprintf(stderr, "Rejecting suspicious path: [%s]", buf);
        buf[0] = '\0';
    }

    (void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int) wbuf_len);
}

#if defined(_WIN32_WCE)
static time_t time(time_t *ptime) {
    time_t t;
    SYSTEMTIME st;
    FILETIME ft;

    GetSystemTime(&st);
    SystemTimeToFileTime(&st, &ft);
    t = SYS2UNIX_TIME(ft.dwLowDateTime, ft.dwHighDateTime);

    if (ptime != NULL) {
        *ptime = t;
    }

    return t;
}

static time_t mktime(struct tm *ptm) {
    SYSTEMTIME st;
    FILETIME ft, lft;

    st.wYear = ptm->tm_year + 1900;
    st.wMonth = ptm->tm_mon + 1;
    st.wDay = ptm->tm_mday;
    st.wHour = ptm->tm_hour;
    st.wMinute = ptm->tm_min;
    st.wSecond = ptm->tm_sec;
    st.wMilliseconds = 0;

    SystemTimeToFileTime(&st, &ft);
    LocalFileTimeToFileTime(&ft, &lft);
    return (time_t) ((MAKEUQUAD(lft.dwLowDateTime, lft.dwHighDateTime) -
                EPOCH_DIFF) / RATE_DIFF);
}

static struct tm *localtime(const time_t *ptime, struct tm *ptm) {
    int64_t t = ((int64_t) *ptime) * RATE_DIFF + EPOCH_DIFF;
    FILETIME ft, lft;
    SYSTEMTIME st;
    TIME_ZONE_INFORMATION tzinfo;

    if (ptm == NULL) {
        return NULL;
    }

    * (int64_t *) &ft = t;
    FileTimeToLocalFileTime(&ft, &lft);
    FileTimeToSystemTime(&lft, &st);
    ptm->tm_year = st.wYear - 1900;
    ptm->tm_mon = st.wMonth - 1;
    ptm->tm_wday = st.wDayOfWeek;
    ptm->tm_mday = st.wDay;
    ptm->tm_hour = st.wHour;
    ptm->tm_min = st.wMinute;
    ptm->tm_sec = st.wSecond;
    ptm->tm_yday = 0; // hope nobody uses this
    ptm->tm_isdst =
        GetTimeZoneInformation(&tzinfo) == TIME_ZONE_ID_DAYLIGHT ? 1 : 0;

    return ptm;
}

static size_t strftime(char *dst, size_t dst_size, const char *fmt,
        const struct tm *tm) {
    (void) snprintf(dst, dst_size, "implement strftime() for WinCE");
    return 0;
}
#endif

static int mg_rename(const char* oldname, const char* newname) {
    wchar_t woldbuf[PATH_MAX];
    wchar_t wnewbuf[PATH_MAX];

    to_unicode(oldname, woldbuf, ARRAY_SIZE(woldbuf));
    to_unicode(newname, wnewbuf, ARRAY_SIZE(wnewbuf));

    return MoveFileW(woldbuf, wnewbuf) ? 0 : -1;
}


static FILE *mg_fopen(const char *path, const char *mode) {
    wchar_t wbuf[PATH_MAX], wmode[20];

    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
    MultiByteToWideChar(CP_UTF8, 0, mode, -1, wmode, ARRAY_SIZE(wmode));

    return _wfopen(wbuf, wmode);
}

static int mg_stat(const char *path, struct mgstat *stp) {
    int ok = -1; // Error
    wchar_t wbuf[PATH_MAX];
    WIN32_FILE_ATTRIBUTE_DATA info;

    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));

    if (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0) {
        stp->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
        stp->mtime = SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
                info.ftLastWriteTime.dwHighDateTime);
        stp->is_directory =
            info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
        ok = 0;  // Success
    }

    return ok;
}

static int mg_remove(const char *path) {
    wchar_t wbuf[PATH_MAX];
    to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
    return DeleteFileW(wbuf) ? 0 : -1;
}

static int mg_mkdir(const char *path, int mode) {
    char buf[PATH_MAX];
    wchar_t wbuf[PATH_MAX];

    mode = 0; // Unused
    mg_strlcpy(buf, path, sizeof(buf));
    change_slashes_to_backslashes(buf);

    (void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, sizeof(wbuf));

    return CreateDirectoryW(wbuf, NULL) ? 0 : -1;
}

// Implementation of POSIX opendir/closedir/readdir for Windows.
static DIR * opendir(const char *name) {
    DIR *dir = NULL;
    wchar_t wpath[PATH_MAX];
    DWORD attrs;

    if (name == NULL) {
        SetLastError(ERROR_BAD_ARGUMENTS);
    } else if ((dir = (DIR *) malloc(sizeof(*dir))) == NULL) {
        SetLastError(ERROR_NOT_ENOUGH_MEMORY);
    } else {
        to_unicode(name, wpath, ARRAY_SIZE(wpath));
        attrs = GetFileAttributesW(wpath);
        if (attrs != 0xFFFFFFFF &&
                ((attrs & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY)) {
            (void) wcscat(wpath, L"\\*");
            dir->handle = FindFirstFileW(wpath, &dir->info);
            dir->result.d_name[0] = '\0';
        } else {
            free(dir);
            dir = NULL;
        }
    }

    return dir;
}

static int closedir(DIR *dir) {
    int result = 0;

    if (dir != NULL) {
        if (dir->handle != INVALID_HANDLE_VALUE)
            result = FindClose(dir->handle) ? 0 : -1;

        free(dir);
    } else {
        result = -1;
        SetLastError(ERROR_BAD_ARGUMENTS);
    }

    return result;
}

struct dirent * readdir(DIR *dir) {
    struct dirent *result = 0;

    if (dir) {
        if (dir->handle != INVALID_HANDLE_VALUE) {
            result = &dir->result;
            (void) WideCharToMultiByte(CP_UTF8, 0,
                    dir->info.cFileName, -1, result->d_name,
                    sizeof(result->d_name), NULL, NULL);

            if (!FindNextFileW(dir->handle, &dir->info)) {
                (void) FindClose(dir->handle);
                dir->handle = INVALID_HANDLE_VALUE;
            }

        } else {
            SetLastError(ERROR_FILE_NOT_FOUND);
        }
    } else {
        SetLastError(ERROR_BAD_ARGUMENTS);
    }

    return result;
}

#define set_close_on_exec(fd) // No FD_CLOEXEC on Windows

static int start_thread(struct mg_context *ctx, mg_thread_func_t func,
        void *param) {
    HANDLE hThread;
    ctx = NULL; // Unused

    hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) func, param, 0,
            NULL);
    if (hThread != NULL) {
        (void) CloseHandle(hThread);
    }

    return hThread == NULL ? -1 : 0;
}

static HANDLE dlopen(const char *dll_name, int flags) {
    wchar_t wbuf[PATH_MAX];
    flags = 0; // Unused
    to_unicode(dll_name, wbuf, ARRAY_SIZE(wbuf));
    return LoadLibraryW(wbuf);
}

#if !defined(NO_CGI)
#define SIGKILL 0
static int kill(pid_t pid, int sig_num) {
    (void) TerminateProcess(pid, sig_num);
    (void) CloseHandle(pid);
    return 0;
}

static pid_t spawn_process(struct mg_connection *conn, const char *prog,
        char *envblk, char *envp[], int fd_stdin,
        int fd_stdout, const char *dir) {
    HANDLE me;
    char *p, *interp, cmdline[PATH_MAX], buf[PATH_MAX];
    FILE *fp;
    STARTUPINFOA si;
    PROCESS_INFORMATION pi;

    envp = NULL; // Unused

    (void) memset(&si, 0, sizeof(si));
    (void) memset(&pi, 0, sizeof(pi));

    // TODO(lsm): redirect CGI errors to the error log file
    si.cb  = sizeof(si);
    si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
    si.wShowWindow = SW_HIDE;

    me = GetCurrentProcess();
    (void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdin), me,
            &si.hStdInput, 0, TRUE, DUPLICATE_SAME_ACCESS);
    (void) DuplicateHandle(me, (HANDLE) _get_osfhandle(fd_stdout), me,
            &si.hStdOutput, 0, TRUE, DUPLICATE_SAME_ACCESS);

    // If CGI file is a script, try to read the interpreter line
    interp = conn->ctx->config[CGI_INTERPRETER];
    if (interp == NULL) {
        buf[2] = '\0';
        if ((fp = fopen(cmdline, "r")) != NULL) {
            (void) fgets(buf, sizeof(buf), fp);
            if (buf[0] != '#' || buf[1] != '!') {
                // First line does not start with "#!". Do not set interpreter.
                buf[2] = '\0';
            } else {
                // Trim whitespaces in interpreter name
                for (p = &buf[strlen(buf) - 1]; p > buf && isspace(*p); p--) {
                    *p = '\0';
                }
            }
            (void) fclose(fp);
        }
        interp = buf + 2;
    }

    (void) mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%s%s%c%s",
            interp, interp[0] == '\0' ? "" : " ", dir, DIRSEP, prog);

    DEBUG_TRACE(("Running [%s]", cmdline));
    if (CreateProcessA(NULL, cmdline, NULL, NULL, TRUE,
                CREATE_NEW_PROCESS_GROUP, envblk, dir, &si, &pi) == 0) {
        cry(conn, "%s: CreateProcess(%s): %d",
                __func__, cmdline, ERRNO);
        pi.hProcess = (pid_t) -1;
    } else {
        (void) close(fd_stdin);
        (void) close(fd_stdout);
    }

    (void) CloseHandle(si.hStdOutput);
    (void) CloseHandle(si.hStdInput);
    (void) CloseHandle(pi.hThread);

    return (pid_t) pi.hProcess;
}
#endif /* !NO_CGI */

static int set_non_blocking_mode(SOCKET sock) {
    unsigned long on = 1;
    return ioctlsocket(sock, FIONBIO, &on);
}

#else
static int mg_stat(const char *path, struct mgstat *stp) {
    struct stat st;
    int ok;

    if (stat(path, &st) == 0) {
        ok = 0;
        stp->size = st.st_size;
        stp->mtime = st.st_mtime;
        stp->is_directory = S_ISDIR(st.st_mode);
    } else {
        ok = -1;
    }

    return ok;
}

static void set_close_on_exec(int fd) {
    (void) fcntl(fd, F_SETFD, FD_CLOEXEC);
}

static int start_thread(struct mg_context *ctx, mg_thread_func_t func,
        void *param) {
    pthread_t thread_id;
    pthread_attr_t attr;
    int retval;

    (void) pthread_attr_init(&attr);
    (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    // TODO(lsm): figure out why mongoose dies on Linux if next line is enabled
    // (void) pthread_attr_setstacksize(&attr, sizeof(struct mg_connection) * 5);

    if ((retval = pthread_create(&thread_id, &attr, func, param)) != 0) {
        cry(fc(ctx), "%s: %s", __func__, strerror(retval));
    }

    return retval;
}

#ifndef NO_CGI
static pid_t spawn_process(struct mg_connection *conn, const char *prog,
        char *envblk, char *envp[], int fd_stdin,
        int fd_stdout, const char *dir) {
    pid_t pid;
    const char *interp;

    envblk = NULL; // Unused

    if ((pid = fork()) == -1) {
        // Parent
        send_http_error(conn, 500, http_500_error, "fork(): %s", strerror(ERRNO));
    } else if (pid == 0) {
        // Child
        if (chdir(dir) != 0) {
            cry(conn, "%s: chdir(%s): %s", __func__, dir, strerror(ERRNO));
        } else if (dup2(fd_stdin, 0) == -1) {
            cry(conn, "%s: dup2(%d, 0): %s", __func__, fd_stdin, strerror(ERRNO));
        } else if (dup2(fd_stdout, 1) == -1) {
            cry(conn, "%s: dup2(%d, 1): %s", __func__, fd_stdout, strerror(ERRNO));
        } else {
            (void) dup2(fd_stdout, 2);
            (void) close(fd_stdin);
            (void) close(fd_stdout);

            // Execute CGI program. No need to lock: new process
            interp = conn->ctx->config[CGI_INTERPRETER];
            if (interp == NULL) {
                (void) execle(prog, prog, NULL, envp);
                cry(conn, "%s: execle(%s): %s", __func__, prog, strerror(ERRNO));
            } else {
                (void) execle(interp, interp, prog, NULL, envp);
                cry(conn, "%s: execle(%s %s): %s", __func__, interp, prog,
                        strerror(ERRNO));
            }
        }
        exit(EXIT_FAILURE);
    } else {
        // Parent. Close stdio descriptors
        (void) close(fd_stdin);
        (void) close(fd_stdout);
    }

    return pid;
}
#endif // !NO_CGI

static int set_non_blocking_mode(SOCKET sock) {
    int flags;

    flags = fcntl(sock, F_GETFL, 0);
    (void) fcntl(sock, F_SETFL, flags | O_NONBLOCK);

    return 0;
}
#endif // _WIN32

// Write data to the IO channel - opened file descriptor, socket or SSL
// descriptor. Return number of bytes written.
static int64_t push(FILE *fp, SOCKET sock, SSL *ssl, const char *buf,
        int64_t len) {
    int64_t sent;
    int n, k;

    sent = 0;
    while (sent < len) {

        /* How many bytes we send in this iteration */
        k = len - sent > INT_MAX ? INT_MAX : (int) (len - sent);

        if (ssl != NULL) {
            n = SSL_write(ssl, buf + sent, k);
        } else if (fp != NULL) {
            n = fwrite(buf + sent, 1, (size_t)k, fp);
            if (ferror(fp))
                n = -1;
        } else {
            n = send(sock, buf + sent, (size_t)k, 0);
        }

        if (n < 0)
            break;

        sent += n;
    }

    return sent;
}

// Read from IO channel - opened file descriptor, socket, or SSL descriptor.
// Return number of bytes read.
static int pull(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int len) {
    int nread;

    if (ssl != NULL) {
        nread = SSL_read(ssl, buf, len);
    } else if (fp != NULL) {
        // Use read() instead of fread(), because if we're reading from the CGI
        // pipe, fread() may block until IO buffer is filled up. We cannot afford
        // to block and must pass all read bytes immediately to the client.
        nread = read(fileno(fp), buf, (size_t) len);
        if (ferror(fp))
            nread = -1;
    } else {
        nread = recv(sock, buf, (size_t) len, 0);
    }

    return nread;
}

int mg_read(struct mg_connection *conn, void *buf, size_t len) {
    int n, buffered_len, nread;
    const char *buffered;

    assert((conn->content_len == -1 && conn->consumed_content == 0) ||
            conn->consumed_content <= conn->content_len);
    DEBUG_TRACE(("%p %zu %lld %lld", buf, len,
                conn->content_len, conn->consumed_content));
    nread = 0;
    if (conn->consumed_content < conn->content_len) {

        // Adjust number of bytes to read.
        int64_t to_read = conn->content_len - conn->consumed_content;
        if (to_read < (int64_t) len) {
            len = (int) to_read;
        }

        // How many bytes of data we have buffered in the request buffer?
        buffered = conn->buf + conn->request_len + conn->consumed_content;
        buffered_len = conn->data_len - conn->request_len;
        assert(buffered_len >= 0);

        // Return buffered data back if we haven't done that yet.
        if (conn->consumed_content < (int64_t) buffered_len) {
            buffered_len -= (int) conn->consumed_content;
            if (len < (size_t) buffered_len) {
                buffered_len = len;
            }
            memcpy(buf, buffered, (size_t)buffered_len);
            len -= buffered_len;
            buf = (char *) buf + buffered_len;
            conn->consumed_content += buffered_len;
            nread = buffered_len;
        }

        // We have returned all buffered data. Read new data from the remote socket.
        while (len > 0) {
            n = pull(NULL, conn->client.sock, conn->ssl, (char *) buf, (int) len);
            if (n <= 0) {
                break;
            }
            buf = (char *) buf + n;
            conn->consumed_content += n;
            nread += n;
            len -= n;
        }
    }
    return nread;
}

int mg_write(struct mg_connection *conn, const void *buf, size_t len) {
    return (int) push(NULL, conn->client.sock, conn->ssl,
            (const char *) buf, (int64_t) len);
}

int mg_printf(struct mg_connection *conn, const char *fmt, ...) {
    char buf[BUFSIZ];
    int len;
    va_list ap;

    va_start(ap, fmt);
    len = mg_vsnprintf(conn, buf, sizeof(buf), fmt, ap);
    va_end(ap);

    return mg_write(conn, buf, (size_t)len);
}

// URL-decode input buffer into destination buffer.
// 0-terminate the destination buffer. Return the length of decoded data.
// form-url-encoded data differs from URI encoding in a way that it
// uses '+' as character for space, see RFC 1866 section 8.2.1
// http://ftp.ics.uci.edu/pub/ietf/html/rfc1866.txt
static size_t url_decode(const char *src, size_t src_len, char *dst,
        size_t dst_len, int is_form_url_encoded) {
    size_t i, j;
    int a, b;
#define HEXTOI(x) (isdigit(x) ? x - '0' : x - 'W')

    for (i = j = 0; i < src_len && j < dst_len - 1; i++, j++) {
        if (src[i] == '%' &&
                isxdigit(* (const unsigned char *) (src + i + 1)) &&
                isxdigit(* (const unsigned char *) (src + i + 2))) {
            a = tolower(* (const unsigned char *) (src + i + 1));
            b = tolower(* (const unsigned char *) (src + i + 2));
            dst[j] = (char) ((HEXTOI(a) << 4) | HEXTOI(b));
            i += 2;
        } else if (is_form_url_encoded && src[i] == '+') {
            dst[j] = ' ';
        } else {
            dst[j] = src[i];
        }
    }

    dst[j] = '\0'; /* Null-terminate the destination */

    return j;
}

// Scan given buffer and fetch the value of the given variable.
// It can be specified in query string, or in the POST data.
// Return NULL if the variable not found, or allocated 0-terminated value.
// It is caller's responsibility to free the returned value.
int mg_get_var(const char *buf, size_t buf_len, const char *name,
        char *dst, size_t dst_len) {
    const char *p, *e, *s;
    size_t name_len, len;

    name_len = strlen(name);
    e = buf + buf_len;
    len = -1;
    dst[0] = '\0';

    // buf is "var1=val1&var2=val2...". Find variable first
    for (p = buf; p != NULL && p + name_len < e; p++) {
        if ((p == buf || p[-1] == '&') && p[name_len] == '=' &&
                !mg_strncasecmp(name, p, name_len)) {

            // Point p to variable value
            p += name_len + 1;

            // Point s to the end of the value
            s = (const char *) memchr(p, '&', (size_t)(e - p));
            if (s == NULL) {
                s = e;
            }
            assert(s >= p);

            // Decode variable into destination buffer
            if ((size_t) (s - p) < dst_len) {
                len = url_decode(p, (size_t)(s - p), dst, dst_len, 1);
            }
            break;
        }
    }

    return len;
}

int mg_get_cookie(const struct mg_connection *conn, const char *cookie_name,
        char *dst, size_t dst_size) {
    const char *s, *p, *end;
    int name_len, len = -1;

    dst[0] = '\0';
    if ((s = mg_get_header(conn, "Cookie")) == NULL) {
        return 0;
    }

    name_len = strlen(cookie_name);
    end = s + strlen(s);

    for (; (s = strstr(s, cookie_name)) != NULL; s += name_len)
        if (s[name_len] == '=') {
            s += name_len + 1;
            if ((p = strchr(s, ' ')) == NULL)
                p = end;
            if (p[-1] == ';')
                p--;
            if (*s == '"' && p[-1] == '"' && p > s + 1) {
                s++;
                p--;
            }
            if ((size_t) (p - s) < dst_size) {
                len = (p - s) + 1;
                mg_strlcpy(dst, s, (size_t)len);
            }
            break;
        }

    return len;
}

// Mongoose allows to specify multiple directories to serve,
// like /var/www,/~bob=/home/bob. That means that root directory depends on URI.
// This function returns root dir for given URI.
static int get_document_root(const struct mg_connection *conn,
        struct vec *document_root) {
    const char *root, *uri;
    int len_of_matched_uri;
    struct vec uri_vec, path_vec;

    uri = conn->request_info.uri;
    len_of_matched_uri = 0;
    root = next_option(conn->ctx->config[DOCUMENT_ROOT], document_root, NULL);

    while ((root = next_option(root, &uri_vec, &path_vec)) != NULL) {
        if (memcmp(uri, uri_vec.ptr, uri_vec.len) == 0) {
            *document_root = path_vec;
            len_of_matched_uri = uri_vec.len;
            break;
        }
    }

    return len_of_matched_uri;
}

static void convert_uri_to_file_name(struct mg_connection *conn,
        const char *uri, char *buf,
        size_t buf_len) {
    struct vec vec;
    int match_len;

    match_len = get_document_root(conn, &vec);
    mg_snprintf(conn, buf, buf_len, "%.*s%s", vec.len, vec.ptr, uri + match_len);

#if defined(_WIN32) && !defined(__SYMBIAN32__)
    change_slashes_to_backslashes(buf);
#endif /* _WIN32 */

    DEBUG_TRACE(("[%s] -> [%s], [%.*s]", uri, buf, (int) vec.len, vec.ptr));
}

static int sslize(struct mg_connection *conn, int (*func)(SSL *)) {
    return (conn->ssl = SSL_new(conn->ctx->ssl_ctx)) != NULL &&
        SSL_set_fd(conn->ssl, conn->client.sock) == 1 &&
        func(conn->ssl) == 1;
}

static struct mg_connection *mg_connect(struct mg_connection *conn,
        const char *host, int port, int use_ssl) {
    struct mg_connection *newconn = NULL;
    struct sockaddr_in sin;
    struct hostent *he;
    int sock;

    if (conn->ctx->ssl_ctx == NULL && use_ssl) {
        cry(conn, "%s: SSL is not initialized", __func__);
    } else if ((he = gethostbyname(host)) == NULL) {
        cry(conn, "%s: gethostbyname(%s): %s", __func__, host, strerror(ERRNO));
    } else if ((sock = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
        cry(conn, "%s: socket: %s", __func__, strerror(ERRNO));
    } else {
        sin.sin_family = AF_INET;
        sin.sin_port = htons((uint16_t) port);
        sin.sin_addr = * (struct in_addr *) he->h_addr_list[0];
        if (connect(sock, (struct sockaddr *) &sin, sizeof(sin)) != 0) {
            cry(conn, "%s: connect(%s:%d): %s", __func__, host, port,
                    strerror(ERRNO));
            closesocket(sock);
        } else if ((newconn = (struct mg_connection *)
                    calloc(1, sizeof(*newconn))) == NULL) {
            cry(conn, "%s: calloc: %s", __func__, strerror(ERRNO));
            closesocket(sock);
        } else {
            newconn->client.sock = sock;
            newconn->client.rsa.u.sin = sin;
            if (use_ssl) {
                sslize(newconn, SSL_connect);
            }
        }
    }

    return newconn;
}

// Check whether full request is buffered. Return:
//   -1  if request is malformed
//    0  if request is not yet fully buffered
//   >0  actual request length, including last \r\n\r\n
static int get_request_len(const char *buf, int buflen) {
    const char *s, *e;
    int len = 0;

    DEBUG_TRACE(("buf: %p, len: %d", buf, buflen));
    for (s = buf, e = s + buflen - 1; len <= 0 && s < e; s++)
        // Control characters are not allowed but >=128 is.
        if (!isprint(* (const unsigned char *) s) && *s != '\r' &&
                *s != '\n' && * (const unsigned char *) s < 128) {
            len = -1;
        } else if (s[0] == '\n' && s[1] == '\n') {
            len = (int) (s - buf) + 2;
        } else if (s[0] == '\n' && &s[1] < e &&
                s[1] == '\r' && s[2] == '\n') {
            len = (int) (s - buf) + 3;
        }

    return len;
}

// Convert month to the month number. Return -1 on error, or month number
static int month_number_to_month_name(const char *s) {
    size_t i;

    for (i = 0; i < ARRAY_SIZE(month_names); i++)
        if (!strcmp(s, month_names[i]))
            return (int) i;

    return -1;
}

// Parse date-time string, and return the corresponding time_t value
static time_t parse_date_string(const char *s) {
    time_t current_time;
    struct tm tm, *tmp;
    char mon[32];
    int sec, min, hour, mday, month, year;

    (void) memset(&tm, 0, sizeof(tm));
    sec = min = hour = mday = month = year = 0;

    if (((sscanf(s, "%d/%3s/%d %d:%d:%d",
                        &mday, mon, &year, &hour, &min, &sec) == 6) ||
                (sscanf(s, "%d %3s %d %d:%d:%d",
                        &mday, mon, &year, &hour, &min, &sec) == 6) ||
                (sscanf(s, "%*3s, %d %3s %d %d:%d:%d",
                        &mday, mon, &year, &hour, &min, &sec) == 6) ||
                (sscanf(s, "%d-%3s-%d %d:%d:%d",
                        &mday, mon, &year, &hour, &min, &sec) == 6)) &&
            (month = month_number_to_month_name(mon)) != -1) {
        tm.tm_mday = mday;
        tm.tm_mon = month;
        tm.tm_year = year;
        tm.tm_hour = hour;
        tm.tm_min = min;
        tm.tm_sec = sec;
    }

    if (tm.tm_year > 1900) {
        tm.tm_year -= 1900;
    } else if (tm.tm_year < 70) {
        tm.tm_year += 100;
    }

    // Set Daylight Saving Time field
    current_time = time(NULL);
    tmp = localtime(&current_time);
    tm.tm_isdst = tmp->tm_isdst;

    return mktime(&tm);
}

// Protect against directory disclosure attack by removing '..',
// excessive '/' and '\' characters
static void remove_double_dots_and_double_slashes(char *s) {
    char *p = s;

    while (*s != '\0') {
        *p++ = *s++;
        if (s[-1] == '/' || s[-1] == '\\') {
            // Skip all following slashes and backslashes
            while (*s == '/' || *s == '\\') {
                s++;
            }

            // Skip all double-dots
            while (*s == '.' && s[1] == '.') {
                s += 2;
            }
        }
    }
    *p = '\0';
}

static const struct {
    const char *extension;
    size_t ext_len;
    const char *mime_type;
    size_t mime_type_len;
} builtin_mime_types[] = {
    {".html", 5, "text/html",   9},
    {".htm", 4, "text/html",   9},
    {".shtm", 5, "text/html",   9},
    {".shtml", 6, "text/html",   9},
    {".css", 4, "text/css",   8},
    {".js",  3, "application/x-javascript", 24},
    {".ico", 4, "image/x-icon",   12},
    {".gif", 4, "image/gif",   9},
    {".jpg", 4, "image/jpeg",   10},
    {".jpeg", 5, "image/jpeg",   10},
    {".png", 4, "image/png",   9},
    {".svg", 4, "image/svg+xml",  13},
    {".torrent", 8, "application/x-bittorrent", 24},
    {".wav", 4, "audio/x-wav",   11},
    {".mp3", 4, "audio/x-mp3",   11},
    {".mid", 4, "audio/mid",   9},
    {".m3u", 4, "audio/x-mpegurl",  15},
    {".ram", 4, "audio/x-pn-realaudio",  20},
    {".xml", 4, "text/xml",   8},
    {".xslt", 5, "application/xml",  15},
    {".ra",  3, "audio/x-pn-realaudio",  20},
    {".doc", 4, "application/msword",  19},
    {".exe", 4, "application/octet-stream", 24},
    {".zip", 4, "application/x-zip-compressed", 28},
    {".xls", 4, "application/excel",  17},
    {".tgz", 4, "application/x-tar-gz",  20},
    {".tar", 4, "application/x-tar",  17},
    {".gz",  3, "application/x-gunzip",  20},
    {".arj", 4, "application/x-arj-compressed", 28},
    {".rar", 4, "application/x-arj-compressed", 28},
    {".rtf", 4, "application/rtf",  15},
    {".pdf", 4, "application/pdf",  15},
    {".swf", 4, "application/x-shockwave-flash",29},
    {".mpg", 4, "video/mpeg",   10},
    {".mpeg", 5, "video/mpeg",   10},
    {".asf", 4, "video/x-ms-asf",  14},
    {".avi", 4, "video/x-msvideo",  15},
    {".bmp", 4, "image/bmp",   9},
    {NULL,  0, NULL,    0}
};

// Look at the "path" extension and figure what mime type it has.
// Store mime type in the vector.
static void get_mime_type(struct mg_context *ctx, const char *path,
        struct vec *vec) {
    struct vec ext_vec, mime_vec;
    const char *list, *ext;
    size_t i, path_len;

    path_len = strlen(path);

    // Scan user-defined mime types first, in case user wants to
    // override default mime types.
    list = ctx->config[EXTRA_MIME_TYPES];
    while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL) {
        // ext now points to the path suffix
        ext = path + path_len - ext_vec.len;
        if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0) {
            *vec = mime_vec;
            return;
        }
    }

    // Now scan built-in mime types
    for (i = 0; builtin_mime_types[i].extension != NULL; i++) {
        ext = path + (path_len - builtin_mime_types[i].ext_len);
        if (path_len > builtin_mime_types[i].ext_len &&
                mg_strcasecmp(ext, builtin_mime_types[i].extension) == 0) {
            vec->ptr = builtin_mime_types[i].mime_type;
            vec->len = builtin_mime_types[i].mime_type_len;
            return;
        }
    }

    // Nothing found. Fall back to "text/plain"
    vec->ptr = "text/plain";
    vec->len = 10;
}

#ifndef HAVE_MD5
typedef struct MD5Context {
    uint32_t buf[4];
    uint32_t bits[2];
    unsigned char in[64];
} MD5_CTX;

#if defined(__BYTE_ORDER) && (__BYTE_ORDER == 1234)
#define byteReverse(buf, len) // Do nothing
#else
static void byteReverse(unsigned char *buf, unsigned longs) {
    uint32_t t;
    do {
        t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
        *(uint32_t *) buf = t;
        buf += 4;
    } while (--longs);
}
#endif

#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

#define MD5STEP(f, w, x, y, z, data, s) \
    ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

// Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
// initialization constants.
static void MD5Init(MD5_CTX *ctx) {
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

static void MD5Transform(uint32_t buf[4], uint32_t const in[16]) {
    register uint32_t a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

static void MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len) {
    uint32_t t;

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
        ctx->bits[1]++;
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;

    if (t) {
        unsigned char *p = (unsigned char *) ctx->in + t;

        t = 64 - t;
        if (len < t) {
            memcpy(p, buf, len);
            return;
        }
        memcpy(p, buf, t);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        buf += t;
        len -= t;
    }

    while (len >= 64) {
        memcpy(ctx->in, buf, 64);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        buf += 64;
        len -= 64;
    }

    memcpy(ctx->in, buf, len);
}

static void MD5Final(unsigned char digest[16], MD5_CTX *ctx) {
    unsigned count;
    unsigned char *p;

    count = (ctx->bits[0] >> 3) & 0x3F;

    p = ctx->in + count;
    *p++ = 0x80;
    count = 64 - 1 - count;
    if (count < 8) {
        memset(p, 0, count);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (uint32_t *) ctx->in);
        memset(ctx->in, 0, 56);
    } else {
        memset(p, 0, count - 8);
    }
    byteReverse(ctx->in, 14);

    ((uint32_t *) ctx->in)[14] = ctx->bits[0];
    ((uint32_t *) ctx->in)[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (uint32_t *) ctx->in);
    byteReverse((unsigned char *) ctx->buf, 4);
    memcpy(digest, ctx->buf, 16);
    memset((char *) ctx, 0, sizeof(*ctx));
}
#endif // !HAVE_MD5

// Stringify binary data. Output buffer must be twice as big as input,
// because each byte takes 2 bytes in string representation
static void bin2str(char *to, const unsigned char *p, size_t len) {
    static const char *hex = "0123456789abcdef";

    for (; len--; p++) {
        *to++ = hex[p[0] >> 4];
        *to++ = hex[p[0] & 0x0f];
    }
    *to = '\0';
}

// Return stringified MD5 hash for list of vectors. Buffer must be 33 bytes.
void mg_md5(char *buf, ...) {
    unsigned char hash[16];
    const char *p;
    va_list ap;
    MD5_CTX ctx;

    MD5Init(&ctx);

    va_start(ap, buf);
    while ((p = va_arg(ap, const char *)) != NULL) {
        MD5Update(&ctx, (const unsigned char *) p, (unsigned) strlen(p));
    }
    va_end(ap);

    MD5Final(hash, &ctx);
    bin2str(buf, hash, sizeof(hash));
}

// Check the user's password, return 1 if OK
static int check_password(const char *method, const char *ha1, const char *uri,
        const char *nonce, const char *nc, const char *cnonce,
        const char *qop, const char *response) {
    char ha2[32 + 1], expected_response[32 + 1];

    // Some of the parameters may be NULL
    if (method == NULL || nonce == NULL || nc == NULL || cnonce == NULL ||
            qop == NULL || response == NULL) {
        return 0;
    }

    // NOTE(lsm): due to a bug in MSIE, we do not compare the URI
    // TODO(lsm): check for authentication timeout
    if (// strcmp(dig->uri, c->ouri) != 0 ||
            strlen(response) != 32
            // || now - strtoul(dig->nonce, NULL, 10) > 3600
       ) {
        return 0;
    }

    mg_md5(ha2, method, ":", uri, NULL);
    mg_md5(expected_response, ha1, ":", nonce, ":", nc,
            ":", cnonce, ":", qop, ":", ha2, NULL);

    return mg_strcasecmp(response, expected_response) == 0;
}

// Use the global passwords file, if specified by auth_gpass option,
// or search for .htpasswd in the requested directory.
static FILE *open_auth_file(struct mg_connection *conn, const char *path) {
    struct mg_context *ctx = conn->ctx;
    char name[PATH_MAX];
    const char *p, *e;
    struct mgstat st;
    FILE *fp;

    if (ctx->config[GLOBAL_PASSWORDS_FILE] != NULL) {
        // Use global passwords file
        fp =  mg_fopen(ctx->config[GLOBAL_PASSWORDS_FILE], "r");
        if (fp == NULL)
            cry(fc(ctx), "fopen(%s): %s",
                    ctx->config[GLOBAL_PASSWORDS_FILE], strerror(ERRNO));
    } else if (!mg_stat(path, &st) && st.is_directory) {
        (void) mg_snprintf(conn, name, sizeof(name), "%s%c%s",
                path, DIRSEP, PASSWORDS_FILE_NAME);
        fp = mg_fopen(name, "r");
    } else {
        // Try to find .htpasswd in requested directory.
        for (p = path, e = p + strlen(p) - 1; e > p; e--)
            if (IS_DIRSEP_CHAR(*e))
                break;
        (void) mg_snprintf(conn, name, sizeof(name), "%.*s%c%s",
                (int) (e - p), p, DIRSEP, PASSWORDS_FILE_NAME);
        fp = mg_fopen(name, "r");
    }

    return fp;
}

// Parsed Authorization header
struct ah {
    char *user, *uri, *cnonce, *response, *qop, *nc, *nonce;
};

static int parse_auth_header(struct mg_connection *conn, char *buf,
        size_t buf_size, struct ah *ah) {
    char *name, *value, *s;
    const char *auth_header;

    if ((auth_header = mg_get_header(conn, "Authorization")) == NULL ||
            mg_strncasecmp(auth_header, "Digest ", 7) != 0) {
        return 0;
    }

    // Make modifiable copy of the auth header
    (void) mg_strlcpy(buf, auth_header + 7, buf_size);

    s = buf;
    (void) memset(ah, 0, sizeof(*ah));

    // Parse authorization header
    for (;;) {
        // Gobble initial spaces
        while (isspace(* (unsigned char *) s)) {
            s++;
        }
        name = skip_quoted(&s, "=", " ", 0);
        /* Value is either quote-delimited, or ends at first comma or space. */
        if (s[0] == '\"') {
            s++;
            value = skip_quoted(&s, "\"", " ", '\\');
            if (s[0] == ',') {
                s++;
            }
        } else {
            value = skip_quoted(&s, ", ", " ", 0);  // IE uses commas, FF uses spaces
        }
        if (*name == '\0') {
            break;
        }

        if (!strcmp(name, "username")) {
            ah->user = value;
        } else if (!strcmp(name, "cnonce")) {
            ah->cnonce = value;
        } else if (!strcmp(name, "response")) {
            ah->response = value;
        } else if (!strcmp(name, "uri")) {
            ah->uri = value;
        } else if (!strcmp(name, "qop")) {
            ah->qop = value;
        } else if (!strcmp(name, "nc")) {
            ah->nc = value;
        } else if (!strcmp(name, "nonce")) {
            ah->nonce = value;
        }
    }

    // CGI needs it as REMOTE_USER
    if (ah->user != NULL) {
        conn->request_info.remote_user = mg_strdup(ah->user);
    } else {
        return 0;
    }

    return 1;
}

// Authorize against the opened passwords file. Return 1 if authorized.
static int authorize(struct mg_connection *conn, FILE *fp) {
    struct ah ah;
    char line[256], f_user[256], ha1[256], f_domain[256], buf[BUFSIZ];

    if (!parse_auth_header(conn, buf, sizeof(buf), &ah)) {
        return 0;
    }

    // Loop over passwords file
    while (fgets(line, sizeof(line), fp) != NULL) {
        if (sscanf(line, "%[^:]:%[^:]:%s", f_user, f_domain, ha1) != 3) {
            continue;
        }

        if (!strcmp(ah.user, f_user) &&
                !strcmp(conn->ctx->config[AUTHENTICATION_DOMAIN], f_domain))
            return check_password(
                    conn->request_info.request_method,
                    ha1, ah.uri, ah.nonce, ah.nc, ah.cnonce, ah.qop,
                    ah.response);
    }

    return 0;
}

// Return 1 if request is authorised, 0 otherwise.
static int check_authorization(struct mg_connection *conn, const char *path) {
    FILE *fp;
    char fname[PATH_MAX];
    struct vec uri_vec, filename_vec;
    const char *list;
    int authorized;

    fp = NULL;
    authorized = 1;

    list = conn->ctx->config[PROTECT_URI];
    while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
        if (!memcmp(conn->request_info.uri, uri_vec.ptr, uri_vec.len)) {
            (void) mg_snprintf(conn, fname, sizeof(fname), "%.*s",
                    filename_vec.len, filename_vec.ptr);
            if ((fp = mg_fopen(fname, "r")) == NULL) {
                cry(conn, "%s: cannot open %s: %s", __func__, fname, strerror(errno));
            }
            break;
        }
    }

    if (fp == NULL) {
        fp = open_auth_file(conn, path);
    }

    if (fp != NULL) {
        authorized = authorize(conn, fp);
        (void) fclose(fp);
    }

    return authorized;
}

static void send_authorization_request(struct mg_connection *conn) {
    conn->request_info.status_code = 401;
    (void) mg_printf(conn,
            "HTTP/1.1 401 Unauthorized\r\n"
            "WWW-Authenticate: Digest qop=\"auth\", "
            "realm=\"%s\", nonce=\"%lu\"\r\n\r\n",
            conn->ctx->config[AUTHENTICATION_DOMAIN],
            (unsigned long) time(NULL));
}

static int is_authorized_for_put(struct mg_connection *conn) {
    FILE *fp;
    int ret = 0;

    fp = conn->ctx->config[PUT_DELETE_PASSWORDS_FILE] == NULL ? NULL :
        mg_fopen(conn->ctx->config[PUT_DELETE_PASSWORDS_FILE], "r");

    if (fp != NULL) {
        ret = authorize(conn, fp);
        (void) fclose(fp);
    }

    return ret;
}

int mg_modify_passwords_file(const char *fname, const char *domain,
        const char *user, const char *pass) {
    int found;
    char line[512], u[512], d[512], ha1[33], tmp[PATH_MAX];
    FILE *fp, *fp2;

    found = 0;
    fp = fp2 = NULL;

    // Regard empty password as no password - remove user record.
    if (pass[0] == '\0') {
        pass = NULL;
    }

    (void) snprintf(tmp, sizeof(tmp), "%s.tmp", fname);

    // Create the file if does not exist
    if ((fp = mg_fopen(fname, "a+")) != NULL) {
        (void) fclose(fp);
    }

    // Open the given file and temporary file
    if ((fp = mg_fopen(fname, "r")) == NULL) {
        return 0;
    } else if ((fp2 = mg_fopen(tmp, "w+")) == NULL) {
        fclose(fp);
        return 0;
    }

    // Copy the stuff to temporary file
    while (fgets(line, sizeof(line), fp) != NULL) {
        if (sscanf(line, "%[^:]:%[^:]:%*s", u, d) != 2) {
            continue;
        }

        if (!strcmp(u, user) && !strcmp(d, domain)) {
            found++;
            if (pass != NULL) {
                mg_md5(ha1, user, ":", domain, ":", pass, NULL);
                fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
            }
        } else {
            (void) fprintf(fp2, "%s", line);
        }
    }

    // If new user, just add it
    if (!found && pass != NULL) {
        mg_md5(ha1, user, ":", domain, ":", pass, NULL);
        (void) fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
    }

    // Close files
    (void) fclose(fp);
    (void) fclose(fp2);

    // Put the temp file in place of real file
    (void) mg_remove(fname);
    (void) mg_rename(tmp, fname);

    return 1;
}

struct de {
    struct mg_connection *conn;
    char *file_name;
    struct mgstat st;
};

static void url_encode(const char *src, char *dst, size_t dst_len) {
    static const char *dont_escape = "._-$,;~()";
    static const char *hex = "0123456789abcdef";
    const char *end = dst + dst_len - 1;

    for (; *src != '\0' && dst < end; src++, dst++) {
        if (isalnum(*(const unsigned char *) src) ||
                strchr(dont_escape, * (const unsigned char *) src) != NULL) {
            *dst = *src;
        } else if (dst + 2 < end) {
            dst[0] = '%';
            dst[1] = hex[(* (const unsigned char *) src) >> 4];
            dst[2] = hex[(* (const unsigned char *) src) & 0xf];
            dst += 2;
        }
    }

    *dst = '\0';
}

static void print_dir_entry(struct de *de) {
    char size[64], mod[64], href[PATH_MAX];

    if (de->st.is_directory) {
        (void) mg_snprintf(de->conn, size, sizeof(size), "%s", "[DIRECTORY]");
    } else {
        // We use (signed) cast below because MSVC 6 compiler cannot
        // convert unsigned __int64 to double. Sigh.
        if (de->st.size < 1024) {
            (void) mg_snprintf(de->conn, size, sizeof(size),
                    "%lu", (unsigned long) de->st.size);
        } else if (de->st.size < 1024 * 1024) {
            (void) mg_snprintf(de->conn, size, sizeof(size),
                    "%.1fk", (double) de->st.size / 1024.0);
        } else if (de->st.size < 1024 * 1024 * 1024) {
            (void) mg_snprintf(de->conn, size, sizeof(size),
                    "%.1fM", (double) de->st.size / 1048576);
        } else {
            (void) mg_snprintf(de->conn, size, sizeof(size),
                    "%.1fG", (double) de->st.size / 1073741824);
        }
    }
    (void) strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M", localtime(&de->st.mtime));
    url_encode(de->file_name, href, sizeof(href));
    de->conn->num_bytes_sent += mg_printf(de->conn,
            "<tr><td><a href=\"%s%s%s\">%s%s</a></td>"
            "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
            de->conn->request_info.uri, href, de->st.is_directory ? "/" : "",
            de->file_name, de->st.is_directory ? "/" : "", mod, size);
}

// This function is called from send_directory() and used for
// sorting directory entries by size, or name, or modification time.
// On windows, __cdecl specification is needed in case if project is built
// with __stdcall convention. qsort always requires __cdels callback.
static int WINCDECL compare_dir_entries(const void *p1, const void *p2) {
    const struct de *a = (const struct de *) p1, *b = (const struct de *) p2;
    const char *query_string = a->conn->request_info.query_string;
    int cmp_result = 0;

    if (query_string == NULL) {
        query_string = "na";
    }

    if (a->st.is_directory && !b->st.is_directory) {
        return -1;  // Always put directories on top
    } else if (!a->st.is_directory && b->st.is_directory) {
        return 1;   // Always put directories on top
    } else if (*query_string == 'n') {
        cmp_result = strcmp(a->file_name, b->file_name);
    } else if (*query_string == 's') {
        cmp_result = a->st.size == b->st.size ? 0 :
            a->st.size > b->st.size ? 1 : -1;
    } else if (*query_string == 'd') {
        cmp_result = a->st.mtime == b->st.mtime ? 0 :
            a->st.mtime > b->st.mtime ? 1 : -1;
    }

    return query_string[1] == 'd' ? -cmp_result : cmp_result;
}

static void handle_directory_request(struct mg_connection *conn,
        const char *dir) {
    struct dirent *dp;
    DIR *dirp;
    struct de *entries = NULL;
    char path[PATH_MAX];
    int i, sort_direction, num_entries = 0, arr_size = 128;

    if ((dirp = opendir(dir)) == NULL) {
        send_http_error(conn, 500, "Cannot open directory",
                "Error: opendir(%s): %s", path, strerror(ERRNO));
        return;
    }

    (void) mg_printf(conn, "%s",
            "HTTP/1.1 200 OK\r\n"
            "Connection: close\r\n"
            "Content-Type: text/html; charset=utf-8\r\n\r\n");

    sort_direction = conn->request_info.query_string != NULL &&
        conn->request_info.query_string[1] == 'd' ? 'a' : 'd';

    while ((dp = readdir(dirp)) != NULL) {

        // Do not show current dir and passwords file
        if (!strcmp(dp->d_name, ".") ||
                !strcmp(dp->d_name, "..") ||
                !strcmp(dp->d_name, PASSWORDS_FILE_NAME))
            continue;

        if (entries == NULL || num_entries >= arr_size) {
            arr_size *= 2;
            entries = (struct de *) realloc(entries,
                    arr_size * sizeof(entries[0]));
        }

        if (entries == NULL) {
            closedir(dirp);
            send_http_error(conn, 500, "Cannot open directory",
                    "%s", "Error: cannot allocate memory");
            return;
        }

        mg_snprintf(conn, path, sizeof(path), "%s%c%s", dir, DIRSEP, dp->d_name);

        // If we don't memset stat structure to zero, mtime will have
        // garbage and strftime() will segfault later on in
        // print_dir_entry(). memset is required only if mg_stat()
        // fails. For more details, see
        // http://code.google.com/p/mongoose/issues/detail?id=79
        if (mg_stat(path, &entries[num_entries].st) != 0) {
            memset(&entries[num_entries].st, 0, sizeof(entries[num_entries].st));
        }

        entries[num_entries].conn = conn;
        entries[num_entries].file_name = mg_strdup(dp->d_name);
        num_entries++;
    }
    (void) closedir(dirp);

    conn->num_bytes_sent += mg_printf(conn,
            "<html><head><title>Index of %s</title>"
            "<style>th {text-align: left;}</style></head>"
            "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
            "<tr><th><a href=\"?n%c\">Name</a></th>"
            "<th><a href=\"?d%c\">Modified</a></th>"
            "<th><a href=\"?s%c\">Size</a></th></tr>"
            "<tr><td colspan=\"3\"><hr></td></tr>",
            conn->request_info.uri, conn->request_info.uri,
            sort_direction, sort_direction, sort_direction);

    // Print first entry - link to a parent directory
    conn->num_bytes_sent += mg_printf(conn,
            "<tr><td><a href=\"%s%s\">%s</a></td>"
            "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
            conn->request_info.uri, "..", "Parent directory", "-", "-");

    // Sort and print directory entries
    qsort(entries, (size_t)num_entries, sizeof(entries[0]), compare_dir_entries);
    for (i = 0; i < num_entries; i++) {
        print_dir_entry(&entries[i]);
        free(entries[i].file_name);
    }
    free(entries);

    conn->num_bytes_sent += mg_printf(conn, "%s", "</table></body></html>");
    conn->request_info.status_code = 200;
}

// Send len bytes from the opened file to the client.
static void send_file_data(struct mg_connection *conn, FILE *fp, int64_t len) {
    char buf[BUFSIZ];
    int to_read, num_read, num_written;

    while (len > 0) {
        // Calculate how much to read from the file in the buffer
        to_read = sizeof(buf);
        if ((int64_t) to_read > len)
            to_read = (int) len;

        // Read from file, exit the loop on error
        if ((num_read = fread(buf, 1, (size_t)to_read, fp)) == 0)
            break;

        // Send read bytes to the client, exit the loop on error
        if ((num_written = mg_write(conn, buf, (size_t)num_read)) != num_read)
            break;

        // Both read and were successful, adjust counters
        conn->num_bytes_sent += num_written;
        len -= num_written;
    }
}

static int parse_range_header(const char *header, int64_t *a, int64_t *b) {
    return sscanf(header, "bytes=%" INT64_FMT "-%" INT64_FMT, a, b);
}

static void handle_file_request(struct mg_connection *conn, const char *path,
        struct mgstat *stp) {
    char date[64], lm[64], etag[64], range[64];
    const char *fmt = "%a, %d %b %Y %H:%M:%S %Z", *msg = "OK", *hdr;
    time_t curtime = time(NULL);
    int64_t cl, r1, r2;
    struct vec mime_vec;
    FILE *fp;
    int n;

    get_mime_type(conn->ctx, path, &mime_vec);
    cl = stp->size;
    conn->request_info.status_code = 200;
    range[0] = '\0';

    if ((fp = mg_fopen(path, "rb")) == NULL) {
        send_http_error(conn, 500, http_500_error,
                "fopen(%s): %s", path, strerror(ERRNO));
        return;
    }
    set_close_on_exec(fileno(fp));

    // If Range: header specified, act accordingly
    r1 = r2 = 0;
    hdr = mg_get_header(conn, "Range");
    if (hdr != NULL && (n = parse_range_header(hdr, &r1, &r2)) > 0) {
        conn->request_info.status_code = 206;
        (void) fseeko(fp, (off_t) r1, SEEK_SET);
        cl = n == 2 ? r2 - r1 + 1: cl - r1;
        (void) mg_snprintf(conn, range, sizeof(range),
                "Content-Range: bytes "
                "%" INT64_FMT "-%"
                INT64_FMT "/%" INT64_FMT "\r\n",
                r1, r1 + cl - 1, stp->size);
        msg = "Partial Content";
    }

    // Prepare Etag, Date, Last-Modified headers
    (void) strftime(date, sizeof(date), fmt, localtime(&curtime));
    (void) strftime(lm, sizeof(lm), fmt, localtime(&stp->mtime));
    (void) mg_snprintf(conn, etag, sizeof(etag), "%lx.%lx",
            (unsigned long) stp->mtime, (unsigned long) stp->size);

    (void) mg_printf(conn,
            "HTTP/1.1 %d %s\r\n"
            "Date: %s\r\n"
            "Last-Modified: %s\r\n"
            "Etag: \"%s\"\r\n"
            "Content-Type: %.*s\r\n"
            "Content-Length: %" INT64_FMT "\r\n"
            "Connection: %s\r\n"
            "Accept-Ranges: bytes\r\n"
            "%s\r\n",
            conn->request_info.status_code, msg, date, lm, etag,
            mime_vec.len, mime_vec.ptr, cl, suggest_connection_header(conn), range);

    if (strcmp(conn->request_info.request_method, "HEAD") != 0) {
        send_file_data(conn, fp, cl);
    }
    (void) fclose(fp);
}

// Parse HTTP headers from the given buffer, advance buffer to the point
// where parsing stopped.
static void parse_http_headers(char **buf, struct mg_request_info *ri) {
    int i;

    for (i = 0; i < (int) ARRAY_SIZE(ri->http_headers); i++) {
        ri->http_headers[i].name = skip_quoted(buf, ":", " ", 0);
        ri->http_headers[i].value = skip(buf, "\r\n");
        if (ri->http_headers[i].name[0] == '\0')
            break;
        ri->num_headers = i + 1;
    }
}

static int is_valid_http_method(const char *method) {
    return !strcmp(method, "GET") || !strcmp(method, "POST") ||
        !strcmp(method, "HEAD") || !strcmp(method, "CONNECT") ||
        !strcmp(method, "PUT") || !strcmp(method, "DELETE");
}

// Parse HTTP request, fill in mg_request_info structure.
static int parse_http_request(char *buf, struct mg_request_info *ri) {
    int status = 0;

    // RFC says that all initial whitespaces should be ingored
    while (*buf != '\0' && isspace(* (unsigned char *) buf)) {
        buf++;
    }

    ri->request_method = skip(&buf, " ");
    ri->uri = skip(&buf, " ");
    ri->http_version = skip(&buf, "\r\n");

    if (is_valid_http_method(ri->request_method) &&
            strncmp(ri->http_version, "HTTP/", 5) == 0) {
        ri->http_version += 5;   /* Skip "HTTP/" */
        parse_http_headers(&buf, ri);
        status = 1;
    }

    return status;
}

// Keep reading the input (either opened file descriptor fd, or socket sock,
// or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
// buffer (which marks the end of HTTP request). Buffer buf may already
// have some data. The length of the data is stored in nread.
// Upon every read operation, increase nread by the number of bytes read.
static int read_request(FILE *fp, SOCKET sock, SSL *ssl, char *buf, int bufsiz,
        int *nread) {
    int n, request_len;

    request_len = 0;
    while (*nread < bufsiz && request_len == 0) {
        n = pull(fp, sock, ssl, buf + *nread, bufsiz - *nread);
        if (n <= 0) {
            break;
        } else {
            *nread += n;
            request_len = get_request_len(buf, *nread);
        }
    }

    return request_len;
}

// For given directory path, substitute it to valid index file.
// Return 0 if index file has been found, -1 if not found.
// If the file is found, it's stats is returned in stp.
static int substitute_index_file(struct mg_connection *conn, char *path,
        size_t path_len, struct mgstat *stp) {
    const char *list = conn->ctx->config[INDEX_FILES];
    struct mgstat st;
    struct vec filename_vec;
    size_t n = strlen(path);
    int found = 0;

    // The 'path' given to us points to the directory. Remove all trailing
    // directory separator characters from the end of the path, and
    // then append single directory separator character.
    while (n > 0 && IS_DIRSEP_CHAR(path[n - 1])) {
        n--;
    }
    path[n] = DIRSEP;

    // Traverse index files list. For each entry, append it to the given
    // path and see if the file exists. If it exists, break the loop
    while ((list = next_option(list, &filename_vec, NULL)) != NULL) {

        // Ignore too long entries that may overflow path buffer
        if (filename_vec.len > path_len - n)
            continue;

        // Prepare full path to the index file
        (void) mg_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);

        // Does it exist?
        if (mg_stat(path, &st) == 0) {
            // Yes it does, break the loop
            *stp = st;
            found = 1;
            break;
        }
    }

    // If no index file exists, restore directory path
    if (!found) {
        path[n] = '\0';
    }

    return found;
}

// Return True if we should reply 304 Not Modified.
static int is_not_modified(const struct mg_connection *conn,
        const struct mgstat *stp) {
    const char *ims = mg_get_header(conn, "If-Modified-Since");
    return ims != NULL && stp->mtime <= parse_date_string(ims);
}

static int forward_body_data(struct mg_connection *conn, FILE *fp,
        SOCKET sock, SSL *ssl) {
    const char *expect, *buffered;
    char buf[BUFSIZ];
    int to_read, nread, buffered_len, success = 0;

    expect = mg_get_header(conn, "Expect");
    assert(fp != NULL);

    if (conn->content_len == -1) {
        send_http_error(conn, 411, "Length Required", "");
    } else if (expect != NULL && mg_strcasecmp(expect, "100-continue")) {
        send_http_error(conn, 417, "Expectation Failed", "");
    } else {
        if (expect != NULL) {
            (void) mg_printf(conn, "%s", "HTTP/1.1 100 Continue\r\n\r\n");
        }

        buffered = conn->buf + conn->request_len;
        buffered_len = conn->data_len - conn->request_len;
        assert(buffered_len >= 0);
        assert(conn->consumed_content == 0);

        if (buffered_len > 0) {
            if ((int64_t) buffered_len > conn->content_len) {
                buffered_len = (int) conn->content_len;
            }
            push(fp, sock, ssl, buffered, (int64_t) buffered_len);
            conn->consumed_content += buffered_len;
        }

        while (conn->consumed_content < conn->content_len) {
            to_read = sizeof(buf);
            if ((int64_t) to_read > conn->content_len - conn->consumed_content) {
                to_read = (int) (conn->content_len - conn->consumed_content);
            }
            nread = pull(NULL, conn->client.sock, conn->ssl, buf, to_read);
            if (nread <= 0 || push(fp, sock, ssl, buf, nread) != nread) {
                break;
            }
            conn->consumed_content += nread;
        }

        if (conn->consumed_content == conn->content_len) {
            success = 1;
        }

        // Each error code path in this function must send an error
        if (!success) {
            send_http_error(conn, 577, http_500_error, "");
        }
    }

    return success;
}

#if !defined(NO_CGI)
// This structure helps to create an environment for the spawned CGI program.
// Environment is an array of "VARIABLE=VALUE\0" ASCIIZ strings,
// last element must be NULL.
// However, on Windows there is a requirement that all these VARIABLE=VALUE\0
// strings must reside in a contiguous buffer. The end of the buffer is
// marked by two '\0' characters.
// We satisfy both worlds: we create an envp array (which is vars), all
// entries are actually pointers inside buf.
struct cgi_env_block {
    struct mg_connection *conn;
    char buf[CGI_ENVIRONMENT_SIZE]; // Environment buffer
    int len; // Space taken
    char *vars[MAX_CGI_ENVIR_VARS]; // char **envp
    int nvars; // Number of variables
};

// Append VARIABLE=VALUE\0 string to the buffer, and add a respective
// pointer into the vars array.
static char *addenv(struct cgi_env_block *block, const char *fmt, ...) {
    int n, space;
    char *added;
    va_list ap;

    // Calculate how much space is left in the buffer
    space = sizeof(block->buf) - block->len - 2;
    assert(space >= 0);

    // Make a pointer to the free space int the buffer
    added = block->buf + block->len;

    // Copy VARIABLE=VALUE\0 string into the free space
    va_start(ap, fmt);
    n = mg_vsnprintf(block->conn, added, (size_t) space, fmt, ap);
    va_end(ap);

    // Make sure we do not overflow buffer and the envp array
    if (n > 0 && n < space &&
            block->nvars < (int) ARRAY_SIZE(block->vars) - 2) {
        // Append a pointer to the added string into the envp array
        block->vars[block->nvars++] = block->buf + block->len;
        // Bump up used length counter. Include \0 terminator
        block->len += n + 1;
    }

    return added;
}

static void prepare_cgi_environment(struct mg_connection *conn,
        const char *prog,
        struct cgi_env_block *blk) {
    const char *s, *slash;
    struct vec var_vec, root;
    char *p;
    int  i;

    blk->len = blk->nvars = 0;
    blk->conn = conn;

    get_document_root(conn, &root);

    addenv(blk, "SERVER_NAME=%s", conn->ctx->config[AUTHENTICATION_DOMAIN]);
    addenv(blk, "SERVER_ROOT=%.*s", root.len, root.ptr);
    addenv(blk, "DOCUMENT_ROOT=%.*s", root.len, root.ptr);

    // Prepare the environment block
    addenv(blk, "%s", "GATEWAY_INTERFACE=CGI/1.1");
    addenv(blk, "%s", "SERVER_PROTOCOL=HTTP/1.1");
    addenv(blk, "%s", "REDIRECT_STATUS=200"); // For PHP
    addenv(blk, "SERVER_PORT=%d", ntohs(conn->client.lsa.u.sin.sin_port));
    addenv(blk, "REQUEST_METHOD=%s", conn->request_info.request_method);
    addenv(blk, "REMOTE_ADDR=%s",
            inet_ntoa(conn->client.rsa.u.sin.sin_addr));
    addenv(blk, "REMOTE_PORT=%d", conn->request_info.remote_port);
    addenv(blk, "REQUEST_URI=%s", conn->request_info.uri);

    // SCRIPT_NAME
    assert(conn->request_info.uri[0] == '/');
    slash = strrchr(conn->request_info.uri, '/');
    if ((s = strrchr(prog, '/')) == NULL)
        s = prog;
    addenv(blk, "SCRIPT_NAME=%.*s%s", slash - conn->request_info.uri,
            conn->request_info.uri, s);

    addenv(blk, "SCRIPT_FILENAME=%s", prog);
    addenv(blk, "PATH_TRANSLATED=%s", prog);
    addenv(blk, "HTTPS=%s", conn->ssl == NULL ? "off" : "on");

    if ((s = mg_get_header(conn, "Content-Type")) != NULL)
        addenv(blk, "CONTENT_TYPE=%s", s);

    if (conn->request_info.query_string != NULL)
        addenv(blk, "QUERY_STRING=%s", conn->request_info.query_string);

    if ((s = mg_get_header(conn, "Content-Length")) != NULL)
        addenv(blk, "CONTENT_LENGTH=%s", s);

    if ((s = getenv("PATH")) != NULL)
        addenv(blk, "PATH=%s", s);

#if defined(_WIN32)
    if ((s = getenv("COMSPEC")) != NULL)
        addenv(blk, "COMSPEC=%s", s);
    if ((s = getenv("SYSTEMROOT")) != NULL)
        addenv(blk, "SYSTEMROOT=%s", s);
#else
    if ((s = getenv("LD_LIBRARY_PATH")) != NULL)
        addenv(blk, "LD_LIBRARY_PATH=%s", s);
#endif /* _WIN32 */

    if ((s = getenv("PERLLIB")) != NULL)
        addenv(blk, "PERLLIB=%s", s);

    if (conn->request_info.remote_user != NULL) {
        addenv(blk, "REMOTE_USER=%s", conn->request_info.remote_user);
        addenv(blk, "%s", "AUTH_TYPE=Digest");
    }

    // Add all headers as HTTP_* variables
    for (i = 0; i < conn->request_info.num_headers; i++) {
        p = addenv(blk, "HTTP_%s=%s",
                conn->request_info.http_headers[i].name,
                conn->request_info.http_headers[i].value);

        // Convert variable name into uppercase, and change - to _
        for (; *p != '=' && *p != '\0'; p++) {
            if (*p == '-')
                *p = '_';
            *p = (char) toupper(* (unsigned char *) p);
        }
    }

    // Add user-specified variables
    s = conn->ctx->config[CGI_ENVIRONMENT];
    while ((s = next_option(s, &var_vec, NULL)) != NULL) {
        addenv(blk, "%.*s", var_vec.len, var_vec.ptr);
    }

    blk->vars[blk->nvars++] = NULL;
    blk->buf[blk->len++] = '\0';

    assert(blk->nvars < (int) ARRAY_SIZE(blk->vars));
    assert(blk->len > 0);
    assert(blk->len < (int) sizeof(blk->buf));
}

static void handle_cgi_request(struct mg_connection *conn, const char *prog) {
    int headers_len, data_len, i, fd_stdin[2], fd_stdout[2];
    const char *status;
    char buf[BUFSIZ], *pbuf, dir[PATH_MAX], *p;
    struct mg_request_info ri;
    struct cgi_env_block blk;
    FILE *in, *out;
    pid_t pid;

    prepare_cgi_environment(conn, prog, &blk);

    // CGI must be executed in its own directory. 'dir' must point to the
    // directory containing executable program, 'p' must point to the
    // executable program name relative to 'dir'.
    (void) mg_snprintf(conn, dir, sizeof(dir), "%s", prog);
    if ((p = strrchr(dir, DIRSEP)) != NULL) {
        *p++ = '\0';
    } else {
        dir[0] = '.', dir[1] = '\0';
        p = (char *) prog;
    }

    pid = (pid_t) -1;
    fd_stdin[0] = fd_stdin[1] = fd_stdout[0] = fd_stdout[1] = -1;
    in = out = NULL;

    if (pipe(fd_stdin) != 0 || pipe(fd_stdout) != 0) {
        send_http_error(conn, 500, http_500_error,
                "Cannot create CGI pipe: %s", strerror(ERRNO));
        goto done;
    } else if ((pid = spawn_process(conn, p, blk.buf, blk.vars,
                    fd_stdin[0], fd_stdout[1], dir)) == (pid_t) -1) {
        goto done;
    } else if ((in = fdopen(fd_stdin[1], "wb")) == NULL ||
            (out = fdopen(fd_stdout[0], "rb")) == NULL) {
        send_http_error(conn, 500, http_500_error,
                "fopen: %s", strerror(ERRNO));
        goto done;
    }

    setbuf(in, NULL);
    setbuf(out, NULL);

    // spawn_process() must close those!
    // If we don't mark them as closed, close() attempt before
    // return from this function throws an exception on Windows.
    // Windows does not like when closed descriptor is closed again.
    fd_stdin[0] = fd_stdout[1] = -1;

    // Send POST data to the CGI process if needed
    if (!strcmp(conn->request_info.request_method, "POST") &&
            !forward_body_data(conn, in, INVALID_SOCKET, NULL)) {
        goto done;
    }

    // Now read CGI reply into a buffer. We need to set correct
    // status code, thus we need to see all HTTP headers first.
    // Do not send anything back to client, until we buffer in all
    // HTTP headers.
    data_len = 0;
    headers_len = read_request(out, INVALID_SOCKET, NULL,
            buf, sizeof(buf), &data_len);
    if (headers_len <= 0) {
        send_http_error(conn, 500, http_500_error,
                "CGI program sent malformed HTTP headers: [%.*s]",
                data_len, buf);
        goto done;
    }
    pbuf = buf;
    buf[headers_len - 1] = '\0';
    parse_http_headers(&pbuf, &ri);

    // Make up and send the status line
    status = get_header(&ri, "Status");
    conn->request_info.status_code = status == NULL ? 200 : atoi(status);
    (void) mg_printf(conn, "HTTP/1.1 %d OK\r\n", conn->request_info.status_code);

    // Send headers
    for (i = 0; i < ri.num_headers; i++) {
        mg_printf(conn, "%s: %s\r\n",
                ri.http_headers[i].name, ri.http_headers[i].value);
    }
    (void) mg_write(conn, "\r\n", 2);

    // Send chunk of data that may be read after the headers
    conn->num_bytes_sent += mg_write(conn, buf + headers_len,
            (size_t)(data_len - headers_len));

    // Read the rest of CGI output and send to the client
    send_file_data(conn, out, INT64_MAX);

done:
    if (pid != (pid_t) -1) {
        kill(pid, SIGKILL);
#if !defined(_WIN32)
        do {} while (waitpid(-1, &i, WNOHANG) > 0);
#endif
    }
    if (fd_stdin[0] != -1) {
        (void) close(fd_stdin[0]);
    }
    if (fd_stdout[1] != -1) {
        (void) close(fd_stdout[1]);
    }

    if (in != NULL) {
        (void) fclose(in);
    } else if (fd_stdin[1] != -1) {
        (void) close(fd_stdin[1]);
    }

    if (out != NULL) {
        (void) fclose(out);
    } else if (fd_stdout[0] != -1) {
        (void) close(fd_stdout[0]);
    }
}
#endif // !NO_CGI

// For a given PUT path, create all intermediate subdirectories
// for given path. Return 0 if the path itself is a directory,
// or -1 on error, 1 if OK.
static int put_dir(const char *path) {
    char buf[PATH_MAX];
    const char *s, *p;
    struct mgstat st;
    size_t len;

    for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
        len = p - path;
        assert(len < sizeof(buf));
        (void) memcpy(buf, path, len);
        buf[len] = '\0';

        // Try to create intermediate directory
        if (mg_stat(buf, &st) == -1 && mg_mkdir(buf, 0755) != 0) {
            return -1;
        }

        // Is path itself a directory?
        if (p[1] == '\0') {
            return 0;
        }
    }

    return 1;
}

static void put_file(struct mg_connection *conn, const char *path) {
    struct mgstat st;
    const char *range;
    int64_t r1, r2;
    FILE *fp;
    int rc;

    conn->request_info.status_code = mg_stat(path, &st) == 0 ? 200 : 201;

    if ((rc = put_dir(path)) == 0) {
        mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n", conn->request_info.status_code);
    } else if (rc == -1) {
        send_http_error(conn, 500, http_500_error,
                "put_dir(%s): %s", path, strerror(ERRNO));
    } else if ((fp = mg_fopen(path, "wb+")) == NULL) {
        send_http_error(conn, 500, http_500_error,
                "fopen(%s): %s", path, strerror(ERRNO));
    } else {
        set_close_on_exec(fileno(fp));
        range = mg_get_header(conn, "Content-Range");
        r1 = r2 = 0;
        if (range != NULL && parse_range_header(range, &r1, &r2) > 0) {
            conn->request_info.status_code = 206;
            // TODO(lsm): handle seek error
            (void) fseeko(fp, (off_t) r1, SEEK_SET);
        }
        if (forward_body_data(conn, fp, INVALID_SOCKET, NULL))
            (void) mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n",
                    conn->request_info.status_code);
        (void) fclose(fp);
    }
}

static void send_ssi_file(struct mg_connection *, const char *, FILE *, int);

static void do_ssi_include(struct mg_connection *conn, const char *ssi,
        char *tag, int include_level) {
    char file_name[BUFSIZ], path[PATH_MAX], *p;
    struct vec root;
    int is_ssi;
    FILE *fp;

    get_document_root(conn, &root);

    // sscanf() is safe here, since send_ssi_file() also uses buffer
    // of size BUFSIZ to get the tag. So strlen(tag) is always < BUFSIZ.
    if (sscanf(tag, " virtual=\"%[^\"]\"", file_name) == 1) {
        // File name is relative to the webserver root
        (void) mg_snprintf(conn, path, sizeof(path), "%.*s%c%s",
                root.len, root.ptr, DIRSEP, file_name);
    } else if (sscanf(tag, " file=\"%[^\"]\"", file_name) == 1) {
        // File name is relative to the webserver working directory
        // or it is absolute system path
        (void) mg_snprintf(conn, path, sizeof(path), "%s", file_name);
    } else if (sscanf(tag, " \"%[^\"]\"", file_name) == 1) {
        // File name is relative to the currect document
        (void) mg_snprintf(conn, path, sizeof(path), "%s", ssi);
        if ((p = strrchr(path, DIRSEP)) != NULL) {
            p[1] = '\0';
        }
        (void) mg_snprintf(conn, path + strlen(path),
                sizeof(path) - strlen(path), "%s", file_name);
    } else {
        cry(conn, "Bad SSI #include: [%s]", tag);
        return;
    }

    if ((fp = mg_fopen(path, "rb")) == NULL) {
        cry(conn, "Cannot open SSI #include: [%s]: fopen(%s): %s",
                tag, path, strerror(ERRNO));
    } else {
        set_close_on_exec(fileno(fp));
        is_ssi = match_extension(path, conn->ctx->config[SSI_EXTENSIONS]);
        if (is_ssi) {
            send_ssi_file(conn, path, fp, include_level + 1);
        } else {
            send_file_data(conn, fp, INT64_MAX);
        }
        (void) fclose(fp);
    }
}

#if !defined(NO_POPEN)
static void do_ssi_exec(struct mg_connection *conn, char *tag) {
    char cmd[BUFSIZ];
    FILE *fp;

    if (sscanf(tag, " \"%[^\"]\"", cmd) != 1) {
        cry(conn, "Bad SSI #exec: [%s]", tag);
    } else if ((fp = popen(cmd, "r")) == NULL) {
        cry(conn, "Cannot SSI #exec: [%s]: %s", cmd, strerror(ERRNO));
    } else {
        send_file_data(conn, fp, INT64_MAX);
        (void) pclose(fp);
    }
}
#endif // !NO_POPEN

static void send_ssi_file(struct mg_connection *conn, const char *path,
        FILE *fp, int include_level) {
    char buf[BUFSIZ];
    int ch, len, in_ssi_tag;

    if (include_level > 10) {
        cry(conn, "SSI #include level is too deep (%s)", path);
        return;
    }

    in_ssi_tag = 0;
    len = 0;

    while ((ch = fgetc(fp)) != EOF) {
        if (in_ssi_tag && ch == '>') {
            in_ssi_tag = 0;
            buf[len++] = (char) ch;
            buf[len] = '\0';
            assert(len <= (int) sizeof(buf));
            if (len < 6 || memcmp(buf, "<!--#", 5) != 0) {
                // Not an SSI tag, pass it
                (void) mg_write(conn, buf, (size_t)len);
            } else {
                if (!memcmp(buf + 5, "include", 7)) {
                    do_ssi_include(conn, path, buf + 12, include_level);
#if !defined(NO_POPEN)
                } else if (!memcmp(buf + 5, "exec", 4)) {
                    do_ssi_exec(conn, buf + 9);
#endif // !NO_POPEN
                } else {
                    cry(conn, "%s: unknown SSI " "command: \"%s\"", path, buf);
                }
            }
            len = 0;
        } else if (in_ssi_tag) {
            if (len == 5 && memcmp(buf, "<!--#", 5) != 0) {
                // Not an SSI tag
                in_ssi_tag = 0;
            } else if (len == (int) sizeof(buf) - 2) {
                cry(conn, "%s: SSI tag is too large", path);
                len = 0;
            }
            buf[len++] = ch & 0xff;
        } else if (ch == '<') {
            in_ssi_tag = 1;
            if (len > 0) {
                (void) mg_write(conn, buf, (size_t)len);
            }
            len = 0;
            buf[len++] = ch & 0xff;
        } else {
            buf[len++] = ch & 0xff;
            if (len == (int) sizeof(buf)) {
                (void) mg_write(conn, buf, (size_t)len);
                len = 0;
            }
        }
    }

    // Send the rest of buffered data
    if (len > 0) {
        (void) mg_write(conn, buf, (size_t)len);
    }
}

static void handle_ssi_file_request(struct mg_connection *conn,
        const char *path) {
    FILE *fp;

    if ((fp = mg_fopen(path, "rb")) == NULL) {
        send_http_error(conn, 500, http_500_error, "fopen(%s): %s", path,
                strerror(ERRNO));
    } else {
        set_close_on_exec(fileno(fp));
        mg_printf(conn, "HTTP/1.1 200 OK\r\n"
                "Content-Type: text/html\r\nConnection: %s\r\n\r\n",
                suggest_connection_header(conn));
        send_ssi_file(conn, path, fp, 0);
        (void) fclose(fp);
    }
}

// This is the heart of the Mongoose's logic.
// This function is called when the request is read, parsed and validated,
// and Mongoose must decide what action to take: serve a file, or
// a directory, or call embedded function, etcetera.
static void handle_request(struct mg_connection *conn) {
    struct mg_request_info *ri = &conn->request_info;
    char path[PATH_MAX];
    int uri_len;
    struct mgstat st;

    if ((conn->request_info.query_string = strchr(ri->uri, '?')) != NULL) {
        * conn->request_info.query_string++ = '\0';
    }
    uri_len = strlen(ri->uri);
    (void) url_decode(ri->uri, (size_t)uri_len, ri->uri, (size_t)(uri_len + 1), 0);
    remove_double_dots_and_double_slashes(ri->uri);
    convert_uri_to_file_name(conn, ri->uri, path, sizeof(path));

    DEBUG_TRACE(("%s", ri->uri));
    debug("%d的request uri为 %s", conn->client.sock, ri->uri);
    if (!check_authorization(conn, path)) {
        debug("%d send_authorization_request", conn->client.sock);
        send_authorization_request(conn);
    } else if (call_user(conn, MG_NEW_REQUEST) != NULL) {
        // Do nothing, callback has served the request
    } else if (strstr(path, PASSWORDS_FILE_NAME)) {
        // Do not allow to view passwords files
        send_http_error(conn, 403, "Forbidden", "Access Forbidden");
    } else if (conn->ctx->config[DOCUMENT_ROOT] == NULL) {
        send_http_error(conn, 404, "Not Found", "Not Found");
    } else if ((!strcmp(ri->request_method, "PUT") ||
                !strcmp(ri->request_method, "DELETE")) &&
            (conn->ctx->config[PUT_DELETE_PASSWORDS_FILE] == NULL ||
             !is_authorized_for_put(conn))) {
        debug("%d send_authorization_request", conn->client.sock);
        send_authorization_request(conn);
    } else if (!strcmp(ri->request_method, "PUT")) {
        debug("%d开始put file", conn->client.sock);
        put_file(conn, path);
    } else if (!strcmp(ri->request_method, "DELETE")) {
        if (mg_remove(path) == 0) {
            send_http_error(conn, 200, "OK", "");
        } else {
            send_http_error(conn, 500, http_500_error, "remove(%s): %s", path,
                    strerror(ERRNO));
        }
    } else if (mg_stat(path, &st) != 0) {
        send_http_error(conn, 404, "Not Found", "%s", "File not found");
    } else if (st.is_directory && ri->uri[uri_len - 1] != '/') {
        (void) mg_printf(conn,
                "HTTP/1.1 301 Moved Permanently\r\n"
                "Location: %s/\r\n\r\n", ri->uri);
    } else if (st.is_directory &&
            !substitute_index_file(conn, path, sizeof(path), &st)) {
        if (!mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING], "yes")) {
            debug("%d开始处理目录请求%s", conn->client.sock, path);
            handle_directory_request(conn, path);
        } else {
            send_http_error(conn, 403, "Directory Listing Denied",
                    "Directory listing denied");
        }
    } else if (match_extension(path, conn->ctx->config[CGI_EXTENSIONS])) {
        if (strcmp(ri->request_method, "POST") &&
                strcmp(ri->request_method, "GET")) {
            send_http_error(conn, 501, "Not Implemented",
                    "Method %s is not implemented", ri->request_method);
        } else {
            debug("%d开始处理cgi请求%s", conn->client.sock, path);
            handle_cgi_request(conn, path);
        }
    } else if (match_extension(path, conn->ctx->config[SSI_EXTENSIONS])) {
        debug("%d开始处理ssi_file请求%s", conn->client.sock, path);
        handle_ssi_file_request(conn, path);
    } else if (is_not_modified(conn, &st)) {
        debug("%d %s Not Modified", conn->client.sock, path);
        send_http_error(conn, 304, "Not Modified", "");
    } else {
        debug("%d开始处理文件请求%s", conn->client.sock, path);
        handle_file_request(conn, path, &st);
    }
}

static void close_all_listening_sockets(struct mg_context *ctx) {
    struct socket *sp, *tmp;
    for (sp = ctx->listening_sockets; sp != NULL; sp = tmp) {
        tmp = sp->next;
        (void) closesocket(sp->sock);
        free(sp);
    }
}

// Valid listening port specification is: [ip_address:]port[s|p]
// Examples: 80, 443s, 127.0.0.1:3128p, 1.2.3.4:8080sp
static int parse_port_string(const struct vec *vec, struct socket *so) {
    struct usa *usa = &so->lsa;
    int a, b, c, d, port, len;

    // MacOS needs that. If we do not zero it, subsequent bind() will fail.
    memset(so, 0, sizeof(*so));

    if (sscanf(vec->ptr, "%d.%d.%d.%d:%d%n", &a, &b, &c, &d, &port, &len) == 5) {
        // IP address to bind to is specified
        usa->u.sin.sin_addr.s_addr = htonl((a << 24) | (b << 16) | (c << 8) | d);
    } else if (sscanf(vec->ptr, "%d%n", &port, &len) == 1) {
        // Only port number is specified. Bind to all addresses
        usa->u.sin.sin_addr.s_addr = htonl(INADDR_ANY);
    } else {
        return 0;
    }
    assert(len > 0 && len <= (int) vec->len);

    if (strchr("sp,", vec->ptr[len]) == NULL) {
        return 0;
    }

    so->is_ssl = vec->ptr[len] == 's';
    so->is_proxy = vec->ptr[len] == 'p';
    usa->len = sizeof(usa->u.sin);
    usa->u.sin.sin_family = AF_INET;
    usa->u.sin.sin_port = htons((uint16_t) port);

    return 1;
}

static int set_ports_option(struct mg_context *ctx) {
    const char *list = ctx->config[LISTENING_PORTS];
    int reuseaddr = 1, success = 1;
    SOCKET sock;
    struct vec vec;
    struct socket so, *listener;

    while (success && (list = next_option(list, &vec, NULL)) != NULL) {
        if (!parse_port_string(&vec, &so)) {
            cry(fc(ctx), "%s: %.*s: invalid port spec. Expecting list of: %s",
                    __func__, vec.len, vec.ptr, "[IP_ADDRESS:]PORT[s|p]");
            success = 0;
        } else if (so.is_ssl && ctx->ssl_ctx == NULL) {
            cry(fc(ctx), "Cannot add SSL socket, is -ssl_cert option set?");
            success = 0;
        } else if ((sock = socket(PF_INET, SOCK_STREAM, 6)) == INVALID_SOCKET ||
#if !defined(_WIN32)
                // On Windows, SO_REUSEADDR is recommended only for
                // broadcast UDP sockets
                setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &reuseaddr,
                    sizeof(reuseaddr)) != 0 ||
#endif // !_WIN32
                bind(sock, &so.lsa.u.sa, so.lsa.len) != 0 ||
                listen(sock, 20) != 0) {
            closesocket(sock);
            cry(fc(ctx), "%s: cannot bind to %.*s: %s", __func__,
                    vec.len, vec.ptr, strerror(ERRNO));
            success = 0;
        } else if ((listener = (struct socket *)
                    calloc(1, sizeof(*listener))) == NULL) {
            closesocket(sock);
            cry(fc(ctx), "%s: %s", __func__, strerror(ERRNO));
            success = 0;
        } else {
            *listener = so;
            listener->sock = sock;
            set_close_on_exec(listener->sock);
            listener->next = ctx->listening_sockets;
            ctx->listening_sockets = listener;
        }
    }

    if (!success) {
        close_all_listening_sockets(ctx);
    }

    return success;
}

static void log_header(const struct mg_connection *conn, const char *header,
        FILE *fp) {
    const char *header_value;

    if ((header_value = mg_get_header(conn, header)) == NULL) {
        (void) fprintf(fp, "%s", " -");
    } else {
        (void) fprintf(fp, " \"%s\"", header_value);
    }
}

static void log_access(const struct mg_connection *conn) {
    const struct mg_request_info *ri;
    FILE *fp;
    char date[64];

    fp = conn->ctx->config[ACCESS_LOG_FILE] == NULL ?  NULL :
        mg_fopen(conn->ctx->config[ACCESS_LOG_FILE], "a+");

    if (fp == NULL)
        return;

    (void) strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z",
            localtime(&conn->birth_time));

    ri = &conn->request_info;

    flockfile(fp);

    (void) fprintf(fp,
            "%s - %s [%s] \"%s %s HTTP/%s\" %d %" INT64_FMT,
            inet_ntoa(conn->client.rsa.u.sin.sin_addr),
            ri->remote_user == NULL ? "-" : ri->remote_user,
            date,
            ri->request_method ? ri->request_method : "-",
            ri->uri ? ri->uri : "-",
            ri->http_version,
            conn->request_info.status_code, conn->num_bytes_sent);
    log_header(conn, "Referer", fp);
    log_header(conn, "User-Agent", fp);
    (void) fputc('\n', fp);
    (void) fflush(fp);

    funlockfile(fp);
    (void) fclose(fp);
}

static int isbyte(int n) {
    return n >= 0 && n <= 255;
}

// Verify given socket address against the ACL.
// Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
static int check_acl(struct mg_context *ctx, const struct usa *usa) {
    int a, b, c, d, n, mask, allowed;
    char flag;
    uint32_t acl_subnet, acl_mask, remote_ip;
    struct vec vec;
    const char *list = ctx->config[ACCESS_CONTROL_LIST];

    if (list == NULL) {
        return 1;
    }

    (void) memcpy(&remote_ip, &usa->u.sin.sin_addr, sizeof(remote_ip));

    // If any ACL is set, deny by default
    allowed = '-';

    while ((list = next_option(list, &vec, NULL)) != NULL) {
        mask = 32;

        if (sscanf(vec.ptr, "%c%d.%d.%d.%d%n", &flag, &a, &b, &c, &d, &n) != 5) {
            cry(fc(ctx), "%s: subnet must be [+|-]x.x.x.x[/x]", __func__);
            return -1;
        } else if (flag != '+' && flag != '-') {
            cry(fc(ctx), "%s: flag must be + or -: [%s]", __func__, vec.ptr);
            return -1;
        } else if (!isbyte(a)||!isbyte(b)||!isbyte(c)||!isbyte(d)) {
            cry(fc(ctx), "%s: bad ip address: [%s]", __func__, vec.ptr);
            return -1;
        } else if (sscanf(vec.ptr + n, "/%d", &mask) == 0) {
            // Do nothing, no mask specified
        } else if (mask < 0 || mask > 32) {
            cry(fc(ctx), "%s: bad subnet mask: %d [%s]", __func__, n, vec.ptr);
            return -1;
        }

        acl_subnet = (a << 24) | (b << 16) | (c << 8) | d;
        acl_mask = mask ? 0xffffffffU << (32 - mask) : 0;

        if (acl_subnet == (ntohl(remote_ip) & acl_mask)) {
            allowed = flag;
        }
    }

    return allowed == '+';
}

static void add_to_set(SOCKET fd, fd_set *set, int *max_fd) {
    FD_SET(fd, set);
    if (fd > (SOCKET) *max_fd) {
        *max_fd = (int) fd;
    }
}

#if !defined(_WIN32)
static int set_uid_option(struct mg_context *ctx) {
    struct passwd *pw;
    const char *uid = ctx->config[RUN_AS_USER];
    int success = 0;

    if (uid == NULL) {
        success = 1;
    } else {
        if ((pw = getpwnam(uid)) == NULL) {
            cry(fc(ctx), "%s: unknown user [%s]", __func__, uid);
        } else if (setgid(pw->pw_gid) == -1) {
            cry(fc(ctx), "%s: setgid(%s): %s", __func__, uid, strerror(errno));
        } else if (setuid(pw->pw_uid) == -1) {
            cry(fc(ctx), "%s: setuid(%s): %s", __func__, uid, strerror(errno));
        } else {
            success = 1;
        }
    }

    return success;
}
#endif // !_WIN32

#if !defined(NO_SSL)
static pthread_mutex_t *ssl_mutexes;

static void ssl_locking_callback(int mode, int mutex_num, const char *file,
        int line) {
    line = 0;    // Unused
    file = NULL; // Unused

    if (mode & CRYPTO_LOCK) {
        (void) pthread_mutex_lock(&ssl_mutexes[mutex_num]);
    } else {
        (void) pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
    }
}

static unsigned long ssl_id_callback(void) {
    return (unsigned long) pthread_self();
}

#if !defined(NO_SSL_DL)
static int load_dll(struct mg_context *ctx, const char *dll_name,
        struct ssl_func *sw) {
    union {void *p; void (*fp)(void);} u;
    void  *dll_handle;
    struct ssl_func *fp;

    if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
        cry(fc(ctx), "%s: cannot load %s", __func__, dll_name);
        return 0;
    }

    for (fp = sw; fp->name != NULL; fp++) {
#ifdef _WIN32
        // GetProcAddress() returns pointer to function
        u.fp = (void (*)(void)) dlsym(dll_handle, fp->name);
#else
        // dlsym() on UNIX returns void *. ISO C forbids casts of data pointers to
        // function pointers. We need to use a union to make a cast.
        u.p = dlsym(dll_handle, fp->name);
#endif /* _WIN32 */
        if (u.fp == NULL) {
            cry(fc(ctx), "%s: %s: cannot find %s", __func__, dll_name, fp->name);
            return 0;
        } else {
            fp->ptr = u.fp;
        }
    }

    return 1;
}
#endif // NO_SSL_DL

// Dynamically load SSL library. Set up ctx->ssl_ctx pointer.
static int set_ssl_option(struct mg_context *ctx) {
    struct mg_request_info request_info;
    SSL_CTX *CTX;
    int i, size;
    const char *pem = ctx->config[SSL_CERTIFICATE];
    const char *chain = ctx->config[SSL_CHAIN_FILE];

    if (pem == NULL) {
        return 1;
    }

#if !defined(NO_SSL_DL)
    if (!load_dll(ctx, SSL_LIB, ssl_sw) ||
            !load_dll(ctx, CRYPTO_LIB, crypto_sw)) {
        return 0;
    }
#endif // NO_SSL_DL

    // Initialize SSL crap
    SSL_library_init();
    SSL_load_error_strings();

    if ((CTX = SSL_CTX_new(SSLv23_server_method())) == NULL) {
        cry(fc(ctx), "SSL_CTX_new error: %s", ssl_error());
    } else if (ctx->user_callback != NULL) {
        memset(&request_info, 0, sizeof(request_info));
        request_info.user_data = ctx->user_data;
        ctx->user_callback(MG_INIT_SSL, (struct mg_connection *) CTX,
                &request_info);
    }

    if (CTX != NULL && SSL_CTX_use_certificate_file(CTX, pem,
                SSL_FILETYPE_PEM) == 0) {
        cry(fc(ctx), "%s: cannot open %s: %s", __func__, pem, ssl_error());
        return 0;
    } else if (CTX != NULL && SSL_CTX_use_PrivateKey_file(CTX, pem,
                SSL_FILETYPE_PEM) == 0) {
        cry(fc(ctx), "%s: cannot open %s: %s", NULL, pem, ssl_error());
        return 0;
    }

    if (CTX != NULL && chain != NULL &&
            SSL_CTX_use_certificate_chain_file(CTX, chain) == 0) {
        cry(fc(ctx), "%s: cannot open %s: %s", NULL, chain, ssl_error());
        return 0;
    }

    // Initialize locking callbacks, needed for thread safety.
    // http://www.openssl.org/support/faq.html#PROG1
    size = sizeof(pthread_mutex_t) * CRYPTO_num_locks();
    if ((ssl_mutexes = (pthread_mutex_t *) malloc((size_t)size)) == NULL) {
        cry(fc(ctx), "%s: cannot allocate mutexes: %s", __func__, ssl_error());
        return 0;
    }

    for (i = 0; i < CRYPTO_num_locks(); i++) {
        pthread_mutex_init(&ssl_mutexes[i], NULL);
    }

    CRYPTO_set_locking_callback(&ssl_locking_callback);
    CRYPTO_set_id_callback(&ssl_id_callback);

    // Done with everything. Save the context.
    ctx->ssl_ctx = CTX;

    return 1;
}
#endif // !NO_SSL

static int set_gpass_option(struct mg_context *ctx) {
    struct mgstat mgstat;
    const char *path = ctx->config[GLOBAL_PASSWORDS_FILE];
    return path == NULL || mg_stat(path, &mgstat) == 0;
}

static int set_acl_option(struct mg_context *ctx) {
    struct usa fake;
    return check_acl(ctx, &fake) != -1;
}

static void reset_per_request_attributes(struct mg_connection *conn) {
    struct mg_request_info *ri = &conn->request_info;

    // Reset request info attributes. DO NOT TOUCH is_ssl, remote_ip, remote_port
    if (ri->remote_user != NULL) {
        free((void *) ri->remote_user);
    }
    ri->remote_user = ri->request_method = ri->uri = ri->http_version = NULL;
    ri->num_headers = 0;
    ri->status_code = -1;

    conn->num_bytes_sent = conn->consumed_content = 0;
    conn->content_len = -1;
    conn->request_len = conn->data_len = 0;
}

static void close_socket_gracefully(SOCKET sock) {
    char buf[BUFSIZ];
    int n;

    // Send FIN to the client
    (void) shutdown(sock, SHUT_WR);
    set_non_blocking_mode(sock);

    // Read and discard pending data. If we do not do that and close the
    // socket, the data in the send buffer may be discarded. This
    // behaviour is seen on Windows, when client keeps sending data
    // when server decide to close the connection; then when client
    // does recv() it gets no data back.
    do {
        n = pull(NULL, sock, NULL, buf, sizeof(buf));
    } while (n > 0);

    // Now we know that our FIN is ACK-ed, safe to close
    (void) closesocket(sock);
}

static void close_connection(struct mg_connection *conn) {
    if (conn->ssl) {
        SSL_free(conn->ssl);
        conn->ssl = NULL;
    }

    if (conn->client.sock != INVALID_SOCKET) {
        close_socket_gracefully(conn->client.sock);
    }
}

static void discard_current_request_from_buffer(struct mg_connection *conn) {
    char *buffered;
    int buffered_len, body_len;

    buffered = conn->buf + conn->request_len;
    buffered_len = conn->data_len - conn->request_len;
    assert(buffered_len >= 0);

    if (conn->content_len == -1) {
        body_len = 0;
    } else if (conn->content_len < (int64_t) buffered_len) {
        body_len = (int) conn->content_len;
    } else {
        body_len = buffered_len;
    }

    conn->data_len -= conn->request_len + body_len;
    memmove(conn->buf, conn->buf + conn->request_len + body_len,
            (size_t) conn->data_len);
}

static int parse_url(const char *url, char *host, int *port) {
    int len;

    if (sscanf(url, "%*[htps]://%1024[^:]:%d%n", host, port, &len) == 2 ||
            sscanf(url, "%1024[^:]:%d%n", host, port, &len) == 2) {
    } else if (sscanf(url, "%*[htps]://%1024[^/]%n", host, &len) == 1) {
        *port = 80;
    } else {
        sscanf(url, "%1024[^/]%n", host, &len);
        *port = 80;
    }
    DEBUG_TRACE(("Host:%s, port:%d", host, *port));

    return len;
}

static void handle_proxy_request(struct mg_connection *conn) {
    struct mg_request_info *ri = &conn->request_info;
    char host[1025], buf[BUFSIZ];
    int port, is_ssl, len, i, n;

    DEBUG_TRACE(("URL: %s", ri->uri));
    if (conn->request_info.uri[0] == '/' ||
            (ri->uri == NULL || (len = parse_url(ri->uri, host, &port))) == 0) {
        return;
    }

    if (conn->peer == NULL) {
        is_ssl = !strcmp(ri->request_method, "CONNECT");
        if ((conn->peer = mg_connect(conn, host, port, is_ssl)) == NULL) {
            return;
        }
        conn->peer->client.is_ssl = is_ssl;
    }

    // Forward client's request to the target
    mg_printf(conn->peer, "%s %s HTTP/%s\r\n", ri->request_method, ri->uri + len,
            ri->http_version);

    // And also all headers. TODO(lsm): anonymize!
    for (i = 0; i < ri->num_headers; i++) {
        mg_printf(conn->peer, "%s: %s\r\n", ri->http_headers[i].name,
                ri->http_headers[i].value);
    }
    // End of headers, final newline
    mg_write(conn->peer, "\r\n", 2);

    // Read and forward body data if any
    if (!strcmp(ri->request_method, "POST")) {
        forward_body_data(conn, NULL, conn->peer->client.sock, conn->peer->ssl);
    }

    // Read data from the target and forward it to the client
    while ((n = pull(NULL, conn->peer->client.sock, conn->peer->ssl,
                    buf, sizeof(buf))) > 0) {
        if (mg_write(conn, buf, (size_t)n) != n) {
            break;
        }
    }

    if (!conn->peer->client.is_ssl) {
        close_connection(conn->peer);
        free(conn->peer);
        conn->peer = NULL;
    }
}

static int is_valid_uri(const char *uri) {
    // Conform to http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2
    // URI can be an asterisk (*) or should start with slash.
    return (uri[0] == '/' || (uri[0] == '*' && uri[1] == '\0'));
}

static void process_new_connection(struct mg_connection *conn) {
    struct mg_request_info *ri = &conn->request_info;
    int keep_alive_enabled;
    const char *cl;

    keep_alive_enabled = !strcmp(conn->ctx->config[ENABLE_KEEP_ALIVE], "yes");

    debug("开始处理连接 %d...", conn->client.sock);
    do {
        reset_per_request_attributes(conn);

        // If next request is not pipelined, read it in
        if ((conn->request_len = get_request_len(conn->buf, conn->data_len)) == 0) {
            debug("%d 读取request", conn->client.sock);
            conn->request_len = read_request(NULL, conn->client.sock, conn->ssl,
                    conn->buf, conn->buf_size, &conn->data_len);
        }
        assert(conn->data_len >= conn->request_len);
        if (conn->request_len == 0 && conn->data_len == conn->buf_size) {
            send_http_error(conn, 413, "Request Too Large", "");
            return;
        } if (conn->request_len <= 0) {
            return;  // Remote end closed the connection
        }

        // Nul-terminate the request cause parse_http_request() uses sscanf
        conn->buf[conn->request_len - 1] = '\0';
        debug("%d解析request",conn->client.sock);
        if (!parse_http_request(conn->buf, ri) ||
                (!conn->client.is_proxy && !is_valid_uri(ri->uri))) {
            // Do not put garbage in the access log, just send it back to the client
            send_http_error(conn, 400, "Bad Request",
                    "Cannot parse HTTP request: [%.*s]", conn->data_len, conn->buf);
        } else if (strcmp(ri->http_version, "1.0") &&
                strcmp(ri->http_version, "1.1")) {
            // Request seems valid, but HTTP version is strange
            send_http_error(conn, 505, "HTTP version not supported", "");
            log_access(conn);
        } else {
            // Request is valid, handle it
            cl = get_header(ri, "Content-Length");
            conn->content_len = cl == NULL ? -1 : strtoll(cl, NULL, 10);
            conn->birth_time = time(NULL);
            if (conn->client.is_proxy) {
                handle_proxy_request(conn);
            } else {
                debug("%d开始handle_request", conn->client.sock);
                handle_request(conn);
            }
            log_access(conn);
            discard_current_request_from_buffer(conn);
        }
        // conn->peer is not NULL only for SSL-ed proxy connections
    } while (conn->peer || (keep_alive_enabled && should_keep_alive(conn)));
    debug("处理连接 %d 结束...", conn->client.sock);
}

// Worker threads take accepted socket from the queue
static int consume_socket(struct mg_context *ctx, struct socket *sp) {
    (void) pthread_mutex_lock(&ctx->mutex);
    DEBUG_TRACE(("going idle"));

    // If the queue is empty, wait. We're idle at this point.
    while (ctx->sq_head == ctx->sq_tail && ctx->stop_flag == 0) {
        pthread_cond_wait(&ctx->sq_full, &ctx->mutex);
    }
    // Master thread could wake us up without putting a socket.
    // If this happens, it is time to exit.
    if (ctx->stop_flag) {
        (void) pthread_mutex_unlock(&ctx->mutex);
        return 0;
    }
    assert(ctx->sq_head > ctx->sq_tail);

    // Copy socket from the queue and increment tail
    *sp = ctx->queue[ctx->sq_tail % ARRAY_SIZE(ctx->queue)];
    ctx->sq_tail++;
    DEBUG_TRACE(("grabbed socket %d, going busy", sp->sock));

    // Wrap pointers if needed
    while (ctx->sq_tail > (int) ARRAY_SIZE(ctx->queue)) {
        ctx->sq_tail -= ARRAY_SIZE(ctx->queue);
        ctx->sq_head -= ARRAY_SIZE(ctx->queue);
    }

    (void) pthread_cond_signal(&ctx->sq_empty);
    (void) pthread_mutex_unlock(&ctx->mutex);

    return 1;
}

static void worker_thread(struct mg_context *ctx) {
    struct mg_connection *conn;
    int buf_size = atoi(ctx->config[MAX_REQUEST_SIZE]);

    conn = (struct mg_connection *) calloc(1, sizeof(*conn) + buf_size);
    conn->buf_size = buf_size;
    conn->buf = (char *) (conn + 1);
    assert(conn != NULL);

    while (ctx->stop_flag == 0 && consume_socket(ctx, &conn->client)) {
        conn->birth_time = time(NULL);
        conn->ctx = ctx;

        // Fill in IP, port info early so even if SSL setup below fails,
        // error handler would have the corresponding info.
        // Thanks to Johannes Winkelmann for the patch.
        conn->request_info.remote_port = ntohs(conn->client.rsa.u.sin.sin_port);
        memcpy(&conn->request_info.remote_ip,
                &conn->client.rsa.u.sin.sin_addr.s_addr, 4);
        conn->request_info.remote_ip = ntohl(conn->request_info.remote_ip);
        conn->request_info.is_ssl = conn->client.is_ssl;

        if (!conn->client.is_ssl ||
                (conn->client.is_ssl && sslize(conn, SSL_accept))) {
            process_new_connection(conn);
        }
        close_connection(conn);
    }
    free(conn);

    // Signal master that we're done with connection and exiting
    (void) pthread_mutex_lock(&ctx->mutex);
    ctx->num_threads--;
    (void) pthread_cond_signal(&ctx->cond);
    assert(ctx->num_threads >= 0);
    (void) pthread_mutex_unlock(&ctx->mutex);

    DEBUG_TRACE(("exiting"));
}

// Master thread adds accepted socket to a queue
static void produce_socket(struct mg_context *ctx, const struct socket *sp) {
    (void) pthread_mutex_lock(&ctx->mutex);

    // If the queue is full, wait
    while (ctx->sq_head - ctx->sq_tail >= (int) ARRAY_SIZE(ctx->queue)) {
        (void) pthread_cond_wait(&ctx->sq_empty, &ctx->mutex);
    }
    debug("current queue size, queue size, %d, %d", ctx->sq_head-ctx->sq_tail, (int)ARRAY_SIZE(ctx->queue));
    assert(ctx->sq_head - ctx->sq_tail < (int) ARRAY_SIZE(ctx->queue));

    // Copy socket to the queue and increment head
    ctx->queue[ctx->sq_head % ARRAY_SIZE(ctx->queue)] = *sp;
    ctx->sq_head++;
    DEBUG_TRACE(("queued socket %d", sp->sock));
    debug("socket %d入队列", sp->sock);

    (void) pthread_cond_signal(&ctx->sq_full);
    (void) pthread_mutex_unlock(&ctx->mutex);
}

static void accept_new_connection(const struct socket *listener,
        struct mg_context *ctx) {
    struct socket accepted;
    int allowed;

    accepted.rsa.len = sizeof(accepted.rsa.u.sin);
    accepted.lsa = listener->lsa;
    accepted.sock = accept(listener->sock, &accepted.rsa.u.sa, &accepted.rsa.len);
    if (accepted.sock != INVALID_SOCKET) {
        allowed = check_acl(ctx, &accepted.rsa);
        if (allowed) {
            // Put accepted socket structure into the queue
            DEBUG_TRACE(("accepted socket %d", accepted.sock));
            debug("accepted socket %d", accepted.sock);
            accepted.is_ssl = listener->is_ssl;
            accepted.is_proxy = listener->is_proxy;
            produce_socket(ctx, &accepted);
        } else {
            cry(fc(ctx), "%s: %s is not allowed to connect",
                    __func__, inet_ntoa(accepted.rsa.u.sin.sin_addr));
            (void) closesocket(accepted.sock);
        }
    }
}

static void master_thread(struct mg_context *ctx) {
    fd_set read_set;
    struct timeval tv;
    struct socket *sp;
    int max_fd;

    while (ctx->stop_flag == 0) {
        FD_ZERO(&read_set);
        max_fd = -1;

        // Add listening sockets to the read set
        for (sp = ctx->listening_sockets; sp != NULL; sp = sp->next) {
            add_to_set(sp->sock, &read_set, &max_fd);
        }

        tv.tv_sec = 0;
        tv.tv_usec = 200 * 1000;

        if (select(max_fd + 1, &read_set, NULL, NULL, &tv) < 0) {
#ifdef _WIN32
            // On windows, if read_set and write_set are empty,
            // select() returns "Invalid parameter" error
            // (at least on my Windows XP Pro). So in this case, we sleep here.
            sleep(1);
#endif // _WIN32
        } else {
            for (sp = ctx->listening_sockets; sp != NULL; sp = sp->next) {
                if (FD_ISSET(sp->sock, &read_set)) {
                    debug("listener %d来了一个新连接",sp->sock);
                    accept_new_connection(sp, ctx);
                }
            }
        }
    }
    DEBUG_TRACE(("stopping workers"));

    // Stop signal received: somebody called mg_stop. Quit.
    close_all_listening_sockets(ctx);

    // Wakeup workers that are waiting for connections to handle.
    pthread_cond_broadcast(&ctx->sq_full);

    // Wait until all threads finish
    (void) pthread_mutex_lock(&ctx->mutex);
    while (ctx->num_threads > 0) {
        (void) pthread_cond_wait(&ctx->cond, &ctx->mutex);
    }
    (void) pthread_mutex_unlock(&ctx->mutex);

    // All threads exited, no sync is needed. Destroy mutex and condvars
    (void) pthread_mutex_destroy(&ctx->mutex);
    (void) pthread_cond_destroy(&ctx->cond);
    (void) pthread_cond_destroy(&ctx->sq_empty);
    (void) pthread_cond_destroy(&ctx->sq_full);

    // Signal mg_stop() that we're done
    ctx->stop_flag = 2;

    DEBUG_TRACE(("exiting"));
}

static void free_context(struct mg_context *ctx) {
    int i;

    // Deallocate config parameters
    for (i = 0; i < NUM_OPTIONS; i++) {
        if (ctx->config[i] != NULL)
            free(ctx->config[i]);
    }

    // Deallocate SSL context
    if (ctx->ssl_ctx != NULL) {
        SSL_CTX_free(ctx->ssl_ctx);
    }
#ifndef NO_SSL
    if (ssl_mutexes != NULL) {
        free(ssl_mutexes);
    }
#endif // !NO_SSL

    // Deallocate context itself
    free(ctx);
}

void mg_stop(struct mg_context *ctx) {
    ctx->stop_flag = 1;

    // Wait until mg_fini() stops
    while (ctx->stop_flag != 2) {
        (void) sleep(0);
    }
    free_context(ctx);

#if defined(_WIN32) && !defined(__SYMBIAN32__)
    (void) WSACleanup();
#endif // _WIN32
}

struct mg_context *mg_start(mg_callback_t user_callback, void *user_data,
        const char **options) {
    struct mg_context *ctx;
    const char *name, *value, *default_value;
    int i;

#if defined(_WIN32) && !defined(__SYMBIAN32__)
    WSADATA data;
    WSAStartup(MAKEWORD(2,2), &data);
#endif // _WIN32

    // Allocate context and initialize reasonable general case defaults.
    // TODO(lsm): do proper error handling here.
    ctx = (struct mg_context *) calloc(1, sizeof(*ctx));
    ctx->user_callback = user_callback;
    ctx->user_data = user_data;

    while (options && (name = *options++) != NULL) {
        if ((i = get_option_index(name)) == -1) {
            cry(fc(ctx), "Invalid option: %s", name);
            free_context(ctx);
            return NULL;
        } else if ((value = *options++) == NULL) {
            cry(fc(ctx), "%s: option value cannot be NULL", name);
            free_context(ctx);
            return NULL;
        }
        ctx->config[i] = mg_strdup(value);
        DEBUG_TRACE(("[%s] -> [%s]", name, value));
    }

    // Set default value if needed
    for (i = 0; config_options[i * ENTRIES_PER_CONFIG_OPTION] != NULL; i++) {
        default_value = config_options[i * ENTRIES_PER_CONFIG_OPTION + 2];
        if (ctx->config[i] == NULL && default_value != NULL) {
            ctx->config[i] = mg_strdup(default_value);
            DEBUG_TRACE(("Setting default: [%s] -> [%s]",
                        config_options[i * ENTRIES_PER_CONFIG_OPTION + 1],
                        default_value));
        }
    }

    // NOTE(lsm): order is important here. SSL certificates must
    // be initialized before listening ports. UID must be set last.
    if (!set_gpass_option(ctx) ||
#if !defined(NO_SSL)
            !set_ssl_option(ctx) ||
#endif
            !set_ports_option(ctx) ||
#if !defined(_WIN32)
            !set_uid_option(ctx) ||
#endif
            !set_acl_option(ctx)) {
        free_context(ctx);
        return NULL;
    }

#if !defined(_WIN32) && !defined(__SYMBIAN32__)
    // Ignore SIGPIPE signal, so if browser cancels the request, it
    // won't kill the whole process.
    (void) signal(SIGPIPE, SIG_IGN);
#endif // !_WIN32

    (void) pthread_mutex_init(&ctx->mutex, NULL);
    (void) pthread_cond_init(&ctx->cond, NULL);
    (void) pthread_cond_init(&ctx->sq_empty, NULL);
    (void) pthread_cond_init(&ctx->sq_full, NULL);

    // Start master (listening) thread
    start_thread(ctx, (mg_thread_func_t) master_thread, ctx);
    debug("start master thread");

    // Start worker threads
    for (i = 0; i < atoi(ctx->config[NUM_THREADS]); i++) {
        if (start_thread(ctx, (mg_thread_func_t) worker_thread, ctx) != 0) {
            cry(fc(ctx), "Cannot start worker thread: %d", ERRNO);
        } else {
            ctx->num_threads++;
            debug("start worker thread %d",ctx->num_threads);
        }
    }

    return ctx;
}
